Survey of Physical Science
By: Dr. David H. Menke
v 1.0
Survey of Physical Sciences
INSTRUCTIONS
Welcome to your Continental Academy course “Survey of the Physical
Sciences”. It is made up of 9 individual lessons, as listed in the Table of
Contents. Each lesson includes practice questions with answers. You will
progress through this course one lesson at a time, at your own pace.
First, study the lesson thoroughly. Then, complete the lesson reviews at the
end of the lesson and carefully check your answers. Sometimes, those
answers will contain information that you will need on the graded lesson
assignments. When you are ready, complete the 10-question, multiple
choice lesson assignment. At the end of each lesson, you will find notes to
help you prepare for the online assignments.
All lesson assignments are open-book. Continue working on the lessons at
your own pace until you have finished all lesson assignments for this
course.
When you have completed and passed all lesson assignments for this
course, complete the End of Course Examination.
If you need help understanding any part of the lesson, practice
questions, or this procedure:
ƒ Click on the “Send a Message” link on the left side of the home
page
ƒ Select “Academic Guidance” in the “To” field
ƒ Type your question in the field provided
ƒ Then, click on the “Send” button
ƒ You will receive a response within ONE BUSINESS DAY
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Survey of Physical Sciences
About the Author…
Dr. David H. Menke was born and raised in the St. Louis area. After high school,
he enrolled at the University of California at Los Angeles, and over the next
eleven years, earned his two bachelor’s degrees, his four master’s degrees, a
teaching credential, and a Ph.D. in Science Education.
During his career, Dr. Menke has served as a public school teacher, community
college instructor, and university professor. He has worked full time at such
institutions as California State University, Northridge; Southern Utah University;
Central Connecticut University; and Broward Community College. Much of his
career was spent as an academic administrator of public observatories and
planetariums.
Dr Menke serves as the First Vice-President and COO of the International
Planetarium Directors Congress, and as Chief Astronomer for the Sossusvlei
Mountain Lodge in Namibia, Africa. As a world traveler, Dr. Menke has served as
leader of many expeditions, including observations of eclipses and comets – on
land and at sea. Dr Menke speaks, reads, and / or writes 16 languages.
Dr Menke is married and has six children ranging in age from 7 to 28. He also
has 4 grandchildren. Dr Menke’s wife is an elementary school teacher and
mental health counselor.
Survey of the Physical Sciences
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Editor: Barry Perlman
Copyright 2008 Home School of America, Inc.
ALL RIGHTS RESERVED
The Continental Academy National Standard Curriculum Series
Published by:
Continental Academy
3241 Executive Way
Miramar, FL 33025
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Survey of Physical Sciences
Physics and chemistry; particularly mechanics, the laws of motion,
energy, the elements, molecules, atoms, sub-atomic particles, nuclear
reactions, light, heat, the periodic table, and chemical changes are
introduced. Astronomy, Geology and Meteorology are surveyed. Each
of the 9 lessons is 10 – 20 pages long with many examples and
practice assignments. A laboratory exercise is part of several of the
lessons. There is a 10-question assignment (which will be graded)
upon the completion of each lesson. There is a 50-question
assignment upon the completion of this course.
™ Student should develop an understanding of the structure of the
atom
™ Student should develop an understanding of the structure and
properties of matter
™ Student should develop an understanding of chemical reactions
™ Student should develop an understanding of motions and forces
™ Student should develop an understanding of conservation of energy
™ Student should develop an understanding of interactions of energy
and matter
™ Student should develop abilities and understandings about scientific
inquiry
™ Student should develop an understanding of natural resources
™ Student should develop an understanding of environmental quality
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TABLE OF CONTENTS
Lesson 1-- The Direction of Time and Space…………………………………7
Lesson 2-- Measures and Motion……………………………………………..19
Lesson 3 - -Energy……………………………………………………………...35
Lesson 4 -- Heat and Waves…………………………………………………..47
Lesson 5 -- Electromagnetic Radiation……………………………………….69
Lesson 6 -- Building Blocks and Nuclear Energy…………………………....79
Lesson 7 -- Chemical Elements………………………..…………………….. 91
Lesson 8 -- Chemical Changes………………………...…………………. 105
Lesson 9 -- Other Physical Sciences .......................................................115
End of Course Review .......................................................................... 137
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LESSON 1 - DIRECTION OF TIME AND SPACE
Time
Clocks, watches, and other devices called “chronometers,” or
“chronographs,” or timepieces measure time. The word “clock” comes from
the Latin word clocca, which means “bell.” In olden days, a clock
tower would ring a bell every hour. The Greek word krono
means, “time” and a meter measures, while a graph records.
Therefore, any timepiece may be referred to as a chronometer or
chronograph. The word “watch” comes from an old English phrase,
waeccan, which means “watchable,” or “worth watching” or “worth looking
at.” In nautical, Greek, and Roman terms, a person’s “watch” meant his
“period of being on duty.” Therefore, we measure out time with a small
timepiece called a watch.
The basic unit is the second, and there are 60 seconds in a minute.
Coming from the Latin word, secundum, which means “division of time,”
we divide an hour into minutes and seconds. One might expect that the
word “minute” would also come from Latin, and it does. Minuta in Latin
used to mean “very small division of time.” Of course, a second is even
smaller.
The length of the second probably came about
since the human heart beats approximately 60
times in one minute – or once per second. Thus,
our measurement of time is based upon a natural
biorhythm.
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Example
Try this simple experiment. Use a watch or clock to determine your
heartbeat rate. Find your pulse (using your wrist or in your throat area), and
then count the number of pulses during a 60-second period. When a
person gets nervous or afraid, the pulse rate goes up. If your pulse rate is
very high, you may wish to consult a physician.
Time Zones
Earth is a sphere, and as such, has a circumference of 360 degrees – just
like a circle. Scientists divided these 360 degrees into 24 different time
zones, each approximately 15 degrees (1,000 miles) wide. The time zones
begin in Greenwich, England, at 0 degrees, and increase by one hour of
time for each 15 degrees eastward. Also, the time decreases one hour for
each 15 degrees westward. Before Time Zone Laws went into effect, each
town, village, and city had its own time, based upon the position of the Sun.
Example
In the old days, when each town had its own time, the time might be 12:10
PM in Boston, Massachusetts, while in Hartford, Connecticut it would be 12
Noon, and in New York City, it would be 11:50 AM.
Now that time zones have been “standardized,” it means that the clocks in
every town and every city within the same time zone have the same time.
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Examples
Every town from Bangor, Maine to Miami, Florida, is in the same time zone.
This is called the Eastern Time Zone or Greenwich Mean Time minus 5
hours. The continental United States has 4 time zones: Eastern, Central,
Mountain, and Pacific. Of course, when one includes Alaska and Hawaii,
that adds more time zones to the U.S. Canada has 5 time zones – 4 that
are exactly the same as those in the continental U.S., and 1 more – a time
zone for the Maritime Provinces of Nova Scotia, Prince Edward Island, and
New Brunswick. These provinces are east of the Eastern Time zone, and
are in the Atlantic Time zone, which is one hour ahead! Canada’s Maritime
Province of Newfoundland has its own time zone, one-half hour ahead of
the Atlantic Time Zone.
Although England is in the Greenwich time zone, most of Western Europe
is one hour ahead – except for Portugal. So, Spain is one hour ahead of
Portugal!
Daylight Savings Time
Daylight Savings Time (DST) is a plan for setting clocks 1 (or 2) hour(s)
ahead so that the sun both rises and sets at a later hour. This gives an
additional hour of daylight in the evening – used mostly during summer
months.
The American Statesman Benjamin Franklin first introduced Daylight
Savings Time in 1764. Later, a Briton, William Willett, advocated it in 1907.
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Daylight Savings Time (DST) has since been used in the United States and
in many European countries since.
During World War I, DST was adopted in order to save energy. Some
places returned to standard time after the war, but others kept DST.
The U.S. Congress passed a law during World War II that placed the entire
country on “war time,” which set clocks 1 hour ahead of standard time.
“War Time” was also followed in the United Kingdom, and clocks were put
ahead 2 hours during summer months.
In peace time, DST was controversial. Farmers were inconvenienced when
they had to conduct business on a different time schedule. Railroads, bus
companies, and airline companies had scheduling problems due to
inconsistencies in various cities and states. In 1966,
Congress passed a law called The Uniform Time Act. It established a
system of uniform daylight saving times throughout the states, exempting
only those states in which the state legislature voted to keep the entire
state on standard time. The states of Arizona and Hawaii do not have DST;
parts of Indiana also do not have DST.
Since 2007, DST begins at 2 AM on the second Sunday of March and ends
at 2 AM on the first Sunday of November.
But what is time and what is its purpose? In the science of relativity discovered by Albert Einstein - we say that “time separates events in
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space.” In other words, if we were to observe a specific location in the
universe for a while, we might notice a variety of “events” occurring over
time. The only thing that separates these “events” is time itself.
Example
A simple example might be a classroom in any school. Let’s say that Mrs.
Jones has a 1st period class in the
subject of English, every weekday
during the school year. Let’s say
that 1st period runs from 8:00 AM to
8:55 AM. Let’s also say that Mrs.
Jones has a 2nd period class in
another subject, like Creative
Writing, and it runs from 9:00 AM to 9:55 AM.
Let’s also say that Mrs. Jones holds these two classes in the exact same
room, Room 202. Thus, Room 202 is defined as a “space.”
Each school day there are many distinct “events” in that space (in Room
202). Event 1 is a lesson in English with a certain group of students. Event
2 is a lesson in Creative Writing with a completely different group of
students. Event 3 may be an “empty” classroom with nothing going on, and
so forth. Perhaps that would be Mrs. Jones’ planning time.
The only thing that separates these three events (the two groups of
students and the planning period) is Time. The space is the same. The
teacher is the same. If time had no meaning, or did not exist, then we might
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expect anything and everything happening in this space in any order. That
would be “chaos” – another branch of physics.
Time is an entity measured by timing devices called chronographs or
chronometers. These include clocks, watches, and other similar tools,
including candles and sundials.
Time always moves forward into the future coming from the past, and is
always in the present. Time never moves backwards, except in science
fiction. Therefore, we refer to time as being one-dimensional.
While time is measured in units of seconds, there are also many other units
of time, developed for convenience, such as minutes, hours, days, weeks,
months, years, decades, centuries, millennia, and eons. We can also divide
the second into milliseconds, microseconds, and even smaller units.
Space
While we often refer to the word “space” when talking about stars and
galaxies, out in “space,” in reality, “space” is a far more important concept.
While Time is one-dimensional, Space, on the other hand, is threedimensional, or 3-D. An artist or an architect would explain space as,
“height, width, and depth.” Height is the up and down dimension,
sometimes called “the y-axis.” Width is the left and right dimension,
sometimes called “the x-axis.” And, finally, depth is the in and out (or
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backwards and forwards) dimension, often called “the z-axis.” We can go
up and down, left and right, backwards and forwards.
Y
-
Space has the units of length, width, and
Z
-
X
X
height, or volume. In science, volume is
in the units of liters. Remember that 1000
mL = 1000 cc = 1000 cm3 = 1.0 liter. This
would be the volume of a cube with a
Z
-
Y
length of 10 cm, width of 10 cm, and height
of 10 cm. When we use only two axes (we pronounce this word “ax-eez,”
so as not to confuse it with the plural of a tool called an “ax”) say, the x-axis
and the z-axis, then that entity is called a “plane.” Don’t confuse this with an
airplane or a field, like a plain in Kansas. The entity is just a “plane.” The xz plane is a two-dimensional flat surface – such as a horizontal tabletop.
The top of a table is two dimensional or 2-D. The wood of the tabletop
itself has thickness, and thus, has components that are three dimensional
or 3-D and into the y-axis. But, in this case, we are referring only to the
surface of the table. The surface of a sheet of paper is also 2-D.
While science fiction often talks of 4 or 5 dimensions of space, we humans
cannot grasp what that may be. Even so, human scientists such as the late
Carl Sagan often discussed the possibility of such dimensions, and how
interesting they may be.
Thus, for now, we recognize only four dimensions: the 1-D of time, and the
3-D of space. We call this “the fabric of space-time,” and it will come up
later.
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Key Terms and Concepts
units of time
units of space
fabric of space time
definition of time
definition of space
Problems
1. Which statement is true about the many time zones around the globe?
a) Each time zone has the same width.
b) Every time zone has a different length.
c) There are 12 time zones around the globe.
d) It is the same date everywhere in the world.
2. Which statement is true about the history of Daylight Savings Time?
a) It started with Ben Franklin, then never changed.
b) It has never been used in wartime.
c) It has never been accepted by the government.
d) Its start and end dates changed in 2007.
3. Where on Earth is it exactly 12 hours ahead of where you live?
a) 12o East
c) half-way around
b) b) 12 hours East
d) all of the way around
4. What can we call a timepiece?
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a) chronograph
c) either a chronograph or chronometer
b) chronometer
d) a timeometer
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5. How many times does the human heart beat per minute?
a) 30
b) 40
c) 20
d) 60
6. How many degrees is each time zone is divided into?
a) 15
b) 20
c) 120
d) 90
7. England is in which time zone?
a) Forward
b) English
c) Greenwich
d) Eastern
8. Who first introduced Daylight Savings Time?
a) George Washington
b) George Takai
c) George Wahl
d) Benjamin Franklin
9. In three dimensions, which set of axes is used to define space?
a) x,y,z
b) y,e,f
c) x,y,t
d) x,q,r
c) 1
d) 100
10. How many liters are 1,000 ml?
a) 5
b) 10
Answers
1. There are 24 times zones around the globe, each approximately 1,000
miles wide in longitude. Choice a. The zones start with Greenwich,
England (at 0 degrees) and increase one hour per time zone as one
moves eastward, and decrease one hour per time zone as one moves
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westward. The International Dateline, which is on the opposite side of
the world from Greenwich at 180 degrees, marks the separation of one
day from another. For example, just west of that line it may be
Wednesday, while just east of that line would still be Tuesday.
2. The history of Daylight Savings Time started with Ben Franklin, then was
brought up by a British scientist, then later used in World Wars I and II.
Eventually our current system was enacted in 1986 and changed in
2007. Choice d.
3. On Earth the place that is exactly 12 hours ahead of the Eastern Time
Zone is in Southeast Asia (Thailand, Indonesia, etc.) Choice c.
4. c Either term may be used
5. d About 60 times a minute
6. a About 15 degrees each
7. c The Greenwich Time Zone
8. d Benjamin Franklin himself
9. a x,y and z
10. c One liter by definition
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LESSON 1 THINGS TO REMEMBER
™ Daylight Savings Time was introduced during WWI
™ If the time is12 Noon in New York City it is 12 Midnight in Bangkok,
Thailand
™ If the time is12 Noon in New York City, it is 12 Noon in Miami
™ A chronometer is the device that indicates time
™ There are 24 time zones around the globe
™ There are 3600 seconds in an hour
™ Time is one-dimensional and space is 3-D
™ A photographic image is two-dimensional
™ A natural biorhythm is the human heart (at rest) beating about
once per second
™ Two liters of soda filling a plastic bottle measures that soda’s
volume
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LESSON 2 - MEASURES AND MOTION
In the physical sciences, we are continually measuring things. The basic
measurements include length (or distance) and mass (or weight). We
measure lengths with rulers, meter sticks, measuring tapes, and various
other tools, including micrometer calipers for very short distances.
In science, the standard unit of length is the meter. A meter is about 39
inches, 3 more inches than a yard. However, a meter is defined as part of
the Earth itself: the distance from the equator to the Geographic North Pole
is exactly 10 million meters.
The “yard” was the distance of a British
king’s arm, so we don’t find that very
scientific. The yard is also equal to three
feet, presumably the typical person’s foot
length. The confusion that exists within this
system of measurement can be illustrated
with the following example. “Yards” and “feet” were developed as social
conventions to standardize measurements and thus facilitate trade.
Example
There’s a story of a grandma sitting on a
porch and knitting 3 socks. “Why are you
knitting 3 socks?” asked a neighbor. “Well,
my grandson told me that he has grown a
foot since he’s been in the Army!”
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Of course, there are units larger and smaller than the meter. For example,
100 centimeters is equal to 1 meter. This is just like 100 cents are equal to
1 dollar. As a comparison, 2.54 centimeters equals 1.0 inch, and 12 inches
equals one foot.
And 1,000 millimeters is the same as 1 meter. Although not used in society
any more, there used to be coins
called mills that were 1/10th of a
cent. A total of 1,000 mills
equaled 1 dollar. People used
these mills in the old days to pay
taxes when the tax on some item
was less than a penny. Most mill
coins were made of plastic.
On the other hand, 1,000 meters
is equal to 1 kilometer, from the word kilo, which means “thousand.” As a
comparison, 1.6 kilometers equals 1.0 mile, or 1.0 kilometer is about 5/8th
of a mile.
People who study the physical sciences use units as small as a nanometer,
an Angstrom, a picometer, and other tiny units; and they use units as large
as megameters, light years, parsecs, and kiloparsecs. In your study of the
physical sciences, you will run across these terms.
Now, one may ask, “What is wrong with inches, feet, yards, and miles?”
Well, nothing really. But science likes to use units based upon constants,
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not on the length of the arm of the local king. Plus, one may notice that all
the metric units are in powers of ten. This decimal system is much easier
to use than the old English standard system.
As another thought, realize that 12 inches equals a foot (not 10 inches), 3
feet equals one yard, and 5,280 feet equals one mile. The decimal system,
usually called the metric system, is not complicated or confusing at all
because it’s based on multiples of ten.
When we measure the weight, or mass, of an object, we again use units in
the metric system. For example, the unit of mass is
the kilogram – or 1,000 grams. Each kilogram
weights about 2.2 pounds at sea level on Earth. But a
kilogram, or a gram, measures mass, not weight.
Mass never changes over time or space, while weight
is really a force, and it is different at each place in
space.
Example
If you weighed 120 pounds on Earth, you’d weigh only 20 pounds on the
Moon. You wouldn’t be thinner, or look any different, but the force of the
Moon’s gravity on you (your weight) would be less. However, if you were 55
kilograms (120 pounds) on Earth, you’d still be 55 kilograms on the Moon,
or anywhere else.
Mass is merely the amount of matter, not how the matter is affected by a
gravitational force field. For convenience, we often say that 1.0-kilogram
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equals 2.2 pounds. But what we really mean is that a 1.0-kilogram object
weighs 2.2 pounds at sea level on the planet Earth.
Example
How much is your mass? Find a
bathroom scale, “weigh” yourself,
and divide that number by 2.2. This
will give you your own mass (in
kilograms).
In sum, we scientists use the units
of seconds, meters, kilograms, and other related measurements.
If an object is NOT moving at all, then it has a set of coordinates, i.e., a
place in space that is identified with a particular value for EACH of the x, y,
and z coordinates (recall the conclusion of Lesson 1).
Example
The city of Ft. Lauderdale, Florida, has a set of coordinates that pinpoints
its position on Earth. These are called the latitude and longitude of this
position. Ft. Lauderdale is approximately 26 degrees north and 80 degrees
west. This means it is 26 degrees north of the Equator, and 80 degrees
west of Greenwich, England. The “z coordinate” would be elevation (feet
above sea level) of 6 feet.
However, very few objects are merely stationary. Even Ft. Lauderdale is
moving – relative to space. Although it is fixed on Earth’s surface, Earth is
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rotating (spinning) at about 1600 kilometers per hour (about 1,000 mph).
Plus, Earth is revolving around the Sun, at about 30 km/sec (about 20
miles/sec). Thus, even though the city of Ft. Lauderdale is not wandering
around Earth’s surface, it is still in motion.
Thus, any and every object is moving. And if it is moving, then it has a
speed, or velocity. It may also
have acceleration; which is
velocity.
The speed of an object is a
measurement of how fast it is
going – usually relative to Earth’s
surface. For example, one may
drive his car at 60 miles per hour. This is the car’s “speed”, which is the
distance traveled over the period of an hour (assuming that the speed is
always at 60 for the entire hour). However, in the physical sciences, we are
more concerned about meters per second.
The fastest speed anything can go is the speed of light, often symbolized
by the letter “c.” Light travels at the incredible speed of about 300,000
kilometers per second, or 300 million meters per second (about 186,282
miles per second). At this amazing speed, one could travel around Earth
seven times in one second, to the Moon in 1¼ second, to the Sun in 8
minutes, to Pluto in 5 hours, and to the nearest star outside of the sun in
just over 4 years.
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Even so, the speed of light is not infinite, as Galileo first believed. Thus,
everything else in the universe travels slower than the speed of light.
Example
So, let’s imagine that you are driving a car down the highway at a speed of
60 miles per hour. Let’s change that into kilometers per hour: 60 miles is
equal to 96 kilometers. Thus, the speed is 96 km/hr. How fast is that in
kilometers per second? There are 3600 seconds in an hour, so 96 km/3600
seconds equals 0.0267 km/sec, or 26.7 meters/second.
In the physical sciences we are more interested in velocity, than speed.
You might ask, “Isn’t it the same thing?” Yes, and no! Both measure how
fast something is going. But velocity also includes the direction that the
object is going.
Example
A speed may be 60 miles per hour (or 26.7 meters per second), but a
velocity would be 60 miles per hour north (or 26.7 meters per second
north). Notice that a direction is added on to the speed to make it a
velocity. That’s really the only difference between speed and velocity. Or,
speed + direction = velocity.
Once we add direction and speed, then the entity becomes a vector. A
vector is like an arrow. No competent archer or woodsman would shoot an
arrow at random. He or she would shoot the arrow towards an object,
whether a deer or an enemy.
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Airline pilots also use the term “vector” to describe the speed and direction
that their airplanes are flying.
Acceleration
Now let’s talk about acceleration. Pretend that you are in a car, and you are
ready to pull out of the driveway onto the street. In order to make your car
“go,” you will have to step onto a floor pedal called the “accelerator.” You
would never step on the brake pedal or some other pedal in order to “go.”
But why is this pedal called the “accelerator” (also known as the “gas
pedal”)? Because when you push this pedal, the automobile speeds up –
i.e., it changes its speed. When you push down on the accelerator, you car
speeds up, or, in other words, you accelerate.
Example
The term “acceleration” means that you are changing the velocity, over
time. You may be traveling at 30 miles per hour north, but then choose to
speed up to 50 miles per hour north. That means that you will have to
increase your velocity from 30 miles per hour north to 50 miles per hour
north – or a difference of 20 miles per hour north. And how long will it take
you to do that? Let’s say it takes 10 seconds. Then you will have an
acceleration of 20 mph/10 sec = 2 mph/sec north.
In the physical sciences, we don’t use the units of miles per hour per
second. Rather, we use meters per square second. No, there is no such
thing as a “square second” like there is a unit called “square feet.” But it is a
term that we use meaning seconds per second. Instead of 2 miles per hour
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per second north, we’d say so many meters per second per second (0.89
m/sec/sec) north, or, for convenience, 0.89 meters per second squared
north. We also would write it 0.89 m/s2 north. It’s just a phrase we use for
convenience.
So, in summary, distance is measured in meters, such as length along the
x-axis. Speed or velocity is distance (in meters) per second, such as
meters/second, or v = x/t along the x-axis, where “t” is the time in seconds.
Acceleration is the change of velocity over time, or (v/t) = (x/t)/t = x/t2. Note
that here “v” represents the change in velocity. Acceleration is the change
of velocity over time. Remember, velocity is speed plus direction. So, if an
object’s direction of motion changes, but its speed does not, that object still
is accelerating. How can this be? This occurs whenever an object’s
motion follows a curved path without speeding up or slowing down.
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Physical Science Lab
I Title: Density of Water
II Purpose: To determine the density of tap water; to learn the proper
scientific method for lab reports; to get used to measuring.
III Equipment Needed
1 - Small glass tumbler
1 – Measuring cup
Scale that weighs ounces of solid food
Tap water
Pen, calculator, lab book, etc.
IV Procedure
1. "Weigh" the empty, dry measuring cup on the scale. Record the answer
in fractions of an ounce. (e.g. 3.5 oz.) [Record all data in Section V (Data
& Calculations) below.]
2. Pour exactly ¼ cup water in measuring cup.
3. "Weigh" the measuring cup with the water in it. Record the answer in
fractions of an ounce.
4. Find the "weight" (i.e., mass) of the water in ounces, and record this. Do
this by subtracting the weight of the dry cup from the one filled with
water. Convert ounces to grams.
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5. Find the density of tap water, by dividing the mass of the water by the
volume of the water 59.15 mL (see below) or (. Give the answer in
grams per milli-liter (mL), which is the same as grams per cubic
centimeter (cc). Record this answer. (Do all calculations in Section V
below). Conversion: ¼ cup water = 2 fluid ounces = 59.15 mL = 59.15
cc.
Conversion: 1.0 pound = 453.6 grams
V. Data & Calculations
1. Mass of dry measuring cup (in fractions of an ounce)
____ oz. ______ grams
2. Mass of cup plus ¼ cup (59.15 mL) of water
_____ oz. _________ grams
3. Mass of the water (subtract #1 from #2)
_________oz. _________ grams
4. Density of the water (Divide #3 by 59.15 mL)
________________ grams/mL
VII Error Analysis
A. Random Errors are ones that you can’t control. However, if you repeat
the experiment several times, all random errors will cancel out
B. Systematic Errors are caused by faulty equipment or from faulty logic
when performing the experiment
C. Personal Errors are caused by the experimenter himself/herself
D. Quantitative Error
The true answer is one gram per cubic centimeter = 1.0 gram/cc =
1.0 g/ml. To find out your percent error (%), here is what you do:
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1. Subtract your answer from the true answer. Then take the positive
difference of that (if the answer is positive, good, if it is not, make it
a positive number by removing the negative sign) or
| True answer – Your answer | = _________
2. Divide this number by the True answer: | T - Y | / T = __________
3. Multiply this number by 100, converting it to a percent (include the
percent sign = ________
E. Qualitative Error
1. Is your answer correct to within 10%? If so, good job, and
congratulations!
2. However, if your answer is more than 10% off, please list some
things that you would tell another experimenter to do (or not do) to
make the answer have a smaller error. In other words, what do
you think contributed to the error?
3. Is your answer more than 100% off? Please do the experiment
again.
VIII Questions (answer from your experiment, or from books, Internet, or
other sources.
1. What is the density of ocean water (salt water)? Is that more, or less,
than the density of tap water?
2. Is it easier for a human to float in the ocean or in a fresh water lake?
Explain why or why not.
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3. Is solid water (ice) denser, or less dense, than liquid water? Explain.
4. How many gallons of water are there on planet Earth?
Key Terms and Concepts
metric system
powers of ten
speed
mass
motion
velocity
weight
rotation
meters per second
length
revolution
acceleration
units in the old system
meters
units in the metric system
meters per square second
Problems
1. Convert 5-foot, 10-inches into centimeters
a) 5.1 cm b) 15 cm
c) 27.6 cm
d) 177.8 cm
2. Convert 200 pounds into kilograms (on Earth)
a) 0.200 kg b) 33.3 kg
c) 90.9 kg
d) 440 kg
3. How many grams are in a kilogram?
a) 0.001 g b) 1.00 g
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c) 1,000 g
d) 1,000,000 g
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4. How did we get the unit of the “yard”?
a) The width of the front yard of the King’s castle.
b) 100 yards is the distance from the first hole to the second hole on
Scotland’s first golf course.
c) 1,000 yards is the width of every time zone.
d) One yard is the length of some king’s arm.
5. Assume that the equator of the Earth is 24,000 miles long (that’s its
circumference). Now, pretend that you are standing somewhere on the
equator, such as in the country of Ecuador. Now, if the Earth turns once,
completely, in 24 hours, then how fast would you be going, even if you
just stood still?
a) 1,000 miles per hour
b) 240 mph
c) 24 mph
d) 0 mph
6. If your Aunt Mary lived 100 miles from you (by car), how fast should you
drive your car (on average) to get to her house in 2 hours? 90 minutes?
1 hour?
a) 100 mph 100 mph
75 mph
b) 50 mph
67 mph 100 mph
c) 25 mph
50 mph
50 mph
d) 10 mph
25 mph
10 mph
7. Now, imagine that you take a road trip of 80 miles, from A to D, but you
have to do it in segments. Let’s say you drive from A to B in 30 minutes,
B to C in 45 minutes, and C to D in 15 minutes. The distance from A to B
is 15 miles; from B to C is 45 miles, and C to D is 20 miles. How many
miles did you drive from A to D? How many minutes did it take you to
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drive from A to D? Convert all those minutes into hours, by dividing by
60 – how many hours did it take you to drive from A to D? What was
your average speed during your trip from A to D?
miles
minutes
hours
mph
a) 80
90
1.5
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b) 80
90
1.0
80
c) 53
80
60
0.88
d) 80
80
1.3
13
8. A racecar driver speeds up from 60 miles per hour to 90 miles per hour
in 3 seconds. What was his/her acceleration?
a) 30 mph b) 30 mph/s
c) 4.44 m/s2
d) 16 km/h
9. One meter is equal to how many millimeters (mm)?
a) 100
b) 1,000
c) 10
d) 100,000
10. The speed of light (c) is the speed limit for the universe.
a) True
b) False
Answers
1. d
3. c
5. a
7. a
9. b
2. c
4. d
6. b
8. c
10. a
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LESSON 2 THINGS TO REMEMBER
™ 5-foot, 10 inches is equal to 178 centimeters
™ 200 pounds is equal to 91 kilograms
™ There are 1,000 grams in a kilogram
™ The unit of a “yard” was the length of a British King’s arm
™ Assume that the equator of the Earth is 24,200 miles in
circumference. Now, pretend that you are standing somewhere on
the equator, such as in the country of Ecuador. Now, if the Earth
turns once, completely, in 24 hours, then you would be going, in miles
per hour, 1,000 even if you were standing still
™ If a person lived 100 miles from you (by car) how fast (miles per hour)
should you drive (by car) to get to that person’s house in 2 hours (100
miles divided by 2 hours would give you 50 miles per hour speed.)
™ To solve certain types of driving distance and average speed
problems, first add up the miles driven then divide by the hours driven
to get the average speed. (Suppose you drive 840 miles in 12 hours,
what is your average speed? 840 miles/12 hours = 70 miles per
hour.)
™ Your weight on Earth is greater than your weight on the moon. And
your weight on the moon would be less than your weight on Earth
™ One pound of solid water is less dense then one pound of liquid water
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LESSON 3 - ENERGY
Momentum
In Latin, the word momentum means “moving power.” In the physical
sciences, momentum is quite simple; in a way, it is the energy of motion.
Here, it’s the mass of an object multiplied by its velocity (therefore, it has a
direction, and is a vector). Momentum is symbolized by the letter “p,” so p =
m x v, where “x” means “multiplied by.” Here, “v” stands for velocity, not a
change in velocity.
“ kg s− m ”
Example
If a 1.0-kilogram object were traveling north at 30 m/s, then the momentum
would be 1 x (30) = 30 kg-m/s.
A slow moving bowling ball has a mass of 10 kilograms and a fast moving
marble has a mass of only 10 grams = 0.01 kg. Each would have the same
momentum if the bowling ball was traveling at 10 m/s and the marble was
traveling at 10 km/second! A fast moving marble can pack a wallop! It is
similar to a bullet, which weighs almost nothing, but travels about 500
meters/second.
In society, we often use the term “momentum” to mean
the energy of motion of a person or a cause. For
example, in 1991 and 1992, Bill Clinton, thengovernor of Arkansas, was able to develop political
“momentum” that propelled him into the White House.
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At first, nobody believed that he had a chance, but he never gave up, and
his momentum was so great, in the end, nobody could stop him.
Force
The Latin word fortis, which means “strong,”
evolved over time to become the word “force.”
Isaac Newton, a British scientist, spent much
of his life studying force. In fact, Newton developed the Three Laws of
Motion, which included the concept of force. Newton was a rare kind of
thinker; he was a genius.
Originally, the first Laws of Motion were discovered in the year 330 BC by
the Greek thinker, Aristotle, who stated:
1. Objects in motion come to rest
2. Objects that go up, must come down
Later, in the early 1600’s, both astronomers Johannes Kepler (a German)
and Galileo Galilei (an Italian) also studied these laws. In the late 1600’s,
Newton developed three, not two, laws:
1. Objects in motion stay in motion, unless an unbalanced external
force is applied.
2. The amount of force needed to accelerate an object is equal to the
mass of an object multiplied by its acceleration, or F = m x a.
3. Every action (force) has an equal and opposite reaction (or force).
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This brings us to the concept of force. As defined above, a force, F, applied
to an object of mass, m, would then accelerate the object at a rate of a.
Necessarily, if the mass is very, very high relative to the force, then the
acceleration will be very, very small, perhaps even close to zero. For
example, if a human exerts a force on a huge concrete building, it won’t
move; thus its acceleration is, zero.
Example
You already know that distance is measured in meters, but you may not
know that force is measured in units called Newtons. Since much of
Newton’s work dealt with the laws of force, the unit of force was named a
“Newton,” in his honor. The Newton is equal to kg-m/s2. Thus, we define
1.0 Newton = 1.0 N = 1.0 kg- m/s2. When a baseball pitcher, or a football
quarterback, or any other such player exerts a force on a ball, it leaves the
hand and quickly accelerates to a maximum speed.
The planet Earth exerts a force on all objects near it. This is the
gravitational force. The force of gravity is equal to the mass of the object
(such as your mass) multiplied by the acceleration due to the gravity of the
planet; in this case, it’s Earth.
You can find out the acceleration of gravity very simply using a piece of
string, a metal washer, a ruler, and a stopwatch. As it turns out, the
acceleration due to gravity on Earth is 9.8 m/s2 (or 32 ft/s2). This means
that if one dropped a marble off the top of a 10-story building, it would keep
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increasing its velocity at the rate of 9.8 m/sec every second. The same
would be true for a bowling ball.
Energy
Energy, from the Greek energos, meaning “active,” is spent when a force
pushes and moves an object. In other words, if you push a baby stroller the
distance of 100 meters, then first you had to exert a force on the baby
stroller, and it had to move a certain distance. It took energy for you to push
that stroller.
Energy is measured in units of “Joule” because a man named Professor
James Joule, a 19th century British scientist who studied energy. Energy
comes in many forms: heat, light, electricity, mechanical, acoustical, and so
forth. A Joule is a unit of force x distance. In a formula, that would be:
E=Fxd
Example
If I exerted 1.0 N of force on an object, and if I were able to move that
object a distance of 1.0 meter, then the energy that I used would be (1.0 N)
x (1.0 m) = 1.0 Newton-meter, which is defined as a Joule.
There are many ways to express energy, and there are many forms of
energy. There’s gravitational energy, potential energy, kinetic energy,
thermal energy, electrical energy, acoustical energy, light energy,
mechanical energy, nuclear energy, and so forth.
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Their units are all measured in Joules, but occasionally one hears of other
units of energy, such as ergs, electron volts, calories, and so forth.
Potential energy (PE) is energy that is stored and available to use in
some way, such as the electrical energy stored in a battery. Gravitational
potential energy (GPE) is nothing more than the energy’s potential at a
certain altitude, i.e., gravitational energy equals the mass times the
acceleration (due to gravity) times the distance that an object can fall, or
GPE = mgh,
where m = mass, g = m/s2, and h = the distance that the object can fall.
This is why waterfalls are excellent sources of gravitational potential
energy. Such natural phenomena are harnessed to change the
gravitational potential energy into hydroelectric power (“hydro” means
water).
Kinetic energy (KE) is the energy of an object as it is traveling at a
certain velocity. The word “kinetic” comes from the Greek word kinetikos,
which means, “to move.” The formula to determine how much kinetic
energy an object has is:
KE = ½ m v2
This means that an object of mass, m, has a kinetic energy, KE, equal to ½
its mass, multiplied by the velocity, v, squared (or v x v = v2). Remember to
square the object’s velocity before multiplying it by half of the object’s
mass.
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Light energy (also known as electromagnetic radiation, or EMR) is the
energy stored in a particle of light (or a wave of light).
In brief, the amount of light energy is equal to a constant multiplied by the
frequency of the light itself, or
E = h v,
where “h” is called “Planck’s constant,” for the German scientist Max
Planck. The symbol, “v,” is the Greek letter for “n,” and is called “nu.” This
sounds just like the word “new.” This symbol stands for something called
“frequency.” One of the laws that we will learn is that the speed of light,
symbolized by the letter, “c,” is not only a constant, with a value of about
300,000 km/s. It also is equal to the wavelength of the light, λ (the small-
case Greek letter lambda), multiplied by the frequency of the light, v. In
other words,
λxv=c
You will learn more about these terms later; just be aware of them for now.
There is also a type of energy called “nuclear energy” or NE. There are
several forms of this, but it is similar to the gravitational energy of a planet
orbiting the Sun, or a moon orbiting a planet. This energy deals with both a
relatively weak force and a strong force. Inside a cell’s nucleus, there is
tremendous energy that keeps the nuclear particles “stuck” together. This is
a very powerful force. If one releases this energy too quickly, it becomes an
atomic, or nuclear, bomb.
Finally, another form of energy is “work.” Essentially, if you do work on
something, then you are using energy. Thus, Force times distance = work,
and the units are expressed in Joules. However, if the object did not move
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(distance = 0), then
Work = F
•
d = F • 0 = 0. NO WORK, no matter
how much force was applied.
Power
Finally, we have mentioned “power” a few times. The word, “power” comes
from a Latin word posse, which means, “to be able to.” This word later
evolved into the French word, “pouvoir,” which also means, “to be able to.”
Eventually this became the word “power” in English.
Power is equal to the amount of energy that one uses in each unit of time,
i.e., Joules per second. In fact, the unit of power is the Watt, named after
yet another scientist, a Scot named James Watt (1736 – 1819). In any
event, if you can spend a lot of energy (or do a lot of work) in a short
period, then you are very powerful. The formula is:
P = E/t
where P is power, E is energy, and t is time.
Examples
Imagine that you had to dig a hole eight feet long, six feet deep, and three
feet wide. It would take a lot of “work” for you to do this; you’d use a lot of
energy.
Now imagine that a much stronger and more energetic woman could dig an
identical hole in just 10 seconds. Amazing, huh? While a fictional character
like Superwoman could do it, a real person could not. Even so,
Superwoman is called “super” for a reason.
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Both you and Superwoman would do the exactly same amount of work,
and use the exact same amount of energy. However, since Superwoman
could do it much faster, it would mean that she was more powerful. Time
means power.
Key Terms and Concepts
Momentum
force
units of momentum
energy
Newton’s Three Laws of Motion
work
The Law of Gravity
power
Problems
1. What is the momentum of a 2000-pound car traveling at 30 miles per
hour? Give the answer in metric units (change pounds to kilograms;
miles per hour to meters per second).
a) 60,000 kg/mph
c) 12,090 kg . m/s
b) 66.7 kg/mph
d) 80,400 kg . m/s
2. How much force does a baseball pitcher have to exert on a 250g
baseball to make it accelerate to a speed of 50 m/s the instant that it
leaves his hand?
a) 12.5 Newtons
c) 12,500 N
b) 25,000 N toward the batter
d) 12.5 N toward the batter
3. How much energy is spent (how much work is done) if that same
baseball travels a distance of 30 meters?
a) 375 J
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b) 12.5 N
c) 12,090 N
d) 30 W
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4. According to Newton's Third Law of motion, what kind of action results
for every action?
a) Like
b) Reactive
c) Reaction
d) Forward
5. The total amount of energy produced by a force of 12 Newtons over a
distance of 3 meters is the same as a force of 6 Newtons over a
distance of 6 meters.
a) True
b) False
6. Which of these does Kinetic Energy not depend on?
a) Mass
b) Speed
c) Distance
d) Velocity
7. If the time it takes for work to be done is reduced, which of these has to
be used?
a) Energy
b) Power
c) Force
d) Mass
8. Gravitational Potential Energy is not dependant on which of these?
a) The mass of the object
b) Acceleration due to gravity
c) The velocity of the object
d) The height of the object
9. Which of the following is the energy of Electromagnetic Radiation
dependant on?
a) Time
b) Frequency
c) Mass
d) Direction
10. The basic unit of work is the _________.
a) Joule
b) Watt
c) Coulomb
d) dyne
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Answers
1. Divide 2000 pounds by 2.2 pounds per kilogram = 909.1 kilograms.
Multiply 30 miles by 1.6 kilometers per mile = 48 kilometers. Now we
have a 909-kg car traveling at 48 km/hour. But we must change it to
meters per second.
48 km = 48,000 meters and 1 hour = 3600
seconds, so divide 48,000 by 3,600 = 13.3 m/sec. So the momentum,
p = m x v = 909 x 13.3 kg . m/sec = 12,090 kg . m/sec (approx).
Choice c
2. Acceleration is change in velocity per second
From 0 m/s (toward the batter) to 50 m/s (toward the batter) in one
second
Equals 50 (m/s)/s or 50 m/s2 (toward the batter).
Since F = m x a, then F = (0.250 kg) x (50 m/s2) =
12.5 kg-m/s2 = 12.5 Newtons toward the batter.
Choice d
3. Since Energy = Work = F x distance =
(12.5) x (30) = 375 Newton-Meters = 375 Joules
4. c opposite
5. a true
6. c distance
7. b power
KE = ½ m v2
Power = work / time
8. c the velocity is not part of GPE = mgh
9. b frequency E = h v,
10. a joule
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LESSON 3 THINGS TO REMEMBER
™ The momentum (in kg-m/sec) of a 910=kg car traveling north at 13.3
meters per second is 12,100. (910 kg X 13.3 m = 12,100 kg-m/sec)
™ The kinetic energy of a 25-gram bullet traveling at 500 m/s is 3.125
KJ
™ The momentum of a 2000 pound car traveling at 30 miles per hour is
12,120 kg-m/sec
™ If you hold a coin between your fingers in the air, the gravitational
potential energy of that coin is greater if the coin is heavier
™ Newton’s Laws of Motion do not include objects
™ Every second that any solid object falls towards Earth, its speed
increases by another 9.8 m/s. After10 seconds of “free fall” all objects
falling are traveling at the same rate of speed.
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LESSON 4 - HEAT AND WAVES
The term “therm” comes from a Greek word for heat. Dynamics is a word
that means the actions that are going on. Thus, “thermodynamics” is the
study of what’s going on with objects that are subjected to a form of energy
called “heat.” A device that measures temperature is a thermometer, which
means, “heat measuring device.”
The thermometer was invented by Galileo, and later
improved by Edmond Halley.
Energy comes in quite a few varieties, and heat is one of
them. One can generate heat in many ways. The most
obvious is by burning, which usually produces a fire and usually smoke.
There are two types of burning: chemical and nuclear. Chemical burning
occurs when an element (atom) or compound (molecule) combines with
oxygen and forms the products of carbon dioxide (CO2) and water (H2O),
as discussed below.
Example
The “formula” for chemical burning, as noted, could be as follows:
2C8H18 + 25O2 = 16CO2 + 18H2O + ENERGY (heat)
The first group (C8H18) is the chemical formula for gasoline, the fuel that
we put in our cars. The second group (O2) is the oxygen molecule. When
your car engine burns gasoline, the stuff that comes out of the exhaust pipe
(muffler) is the third group (CO2), or carbon dioxide, and the last group is
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(H2O), or water vapor. The numbers in front of the groups (2, 25, 16, 18)
are the ratios of the molecules in the mixture.
This will be covered later in our lesson on Chemistry. Notice that one of the
end products is ENERGY, in the form of heat. You may have noticed that
your car engine gets hot after running a while.
This type of reaction is a “one way” street. We can’t take water and carbon
dioxide, heat them up, and create gasoline and free oxygen. The Laws of
Thermodynamics will not allow this burning to be a reversible process.
Interesting Background on
Hydrocarbon Fuels
Ideally, it would be wonderful
if gasoline (which is one of
many types of hydrocarbons)
burns efficiently, that 100% of
it becomes water and carbon
dioxide. Unfortunately, we have never been able to make an engine that is
100% efficient. So, in reality, other particles come out of our cars’ tail
pipes, including deadly carbon monoxide (CO).
Hydrocarbon fuels that combine with oxygen to give off heat include:
methane (CH4), acetylene (C2H2), propane (C3H8), butane (C4H10), gasoline
(C8H18), turpentine (C10H16), kerosenes (C12H26 to C15H32), and paraffin
(C30H62). Methane is also known as “natural gas” and is used as a fuel for
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gas ranges and ovens in many home kitchens. Acetylene is a gas that
burns very hot, and is used in welder’s torches. Propane is a gas that many
campers and outdoor enthusiasts use to fuel their barbecue grills.
Butane is a liquid under pressure, but a gas at room temperature. Butane
burns well, and is the main component in cigar and cigarette lighters.
Gasoline is a liquid, of course. Turpentine is a liquid that we use to thin, or
remove, paint. Kerosenes are liquids, and more of a type of “fuel oil” than a
gasoline – although, thinner than fuel oil. Oil lamps burn kerosene. Some
homeowners choose to heat their homes with “fuel oil”. Wax candles are
mostly paraffin.
Many of the hydrocarbons burn very fast – explosively – like methane,
propane, and gasoline. However, the heavier hydrocarbons burn much
more slowly, like the paraffin in wax candles.
Do not confuse “hydrocarbons” with “carbohydrates”. They sound similar,
and their chemical formulas are similar, but while cars can “eat”
hydrocarbons, humans cannot. Even so, humans can eat carbohydrates
(like potatoes, etc.), but cars cannot.
Do not confuse “gasoline” with “gas”. A gas is any substance that expands
to completely fill its container (like body odor, oxygen gas, water vapor), not
gasoline!
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Measuring Heat
The tool we humans devised to measure heat is
called a “thermometer.” And in order to measure
heat on a thermometer, we need numbers on it.
Most Americans use the Fahrenheit scale to
measure temperature. A German scientist
named Gabriel Fahrenheit developed this in the
1700’s. He developed this scale to go along with
his new invention, the mercury thermometer.
Earlier liquid thermometers used colored alcohol,
but Fahrenheit used the liquid metal mercury.
Anyway, the Fahrenheit scale is somewhat
awkward, so we will start with it.
There are some important “numbers” in Fahrenheit (F) degrees. For
example, 68o F is “room temperature,” although many people feel that is
still cool. We often hear that certain temperatures are “freezing,” when in
reality 32o F is the temperature needed for water to freeze (turn from liquid
to solid). The boiling point of water is 212o F. Normal body temperature is
98.6o F. While we have become familiar with these numbers, they aren’t
“round” numbers, nor are they based upon science. For example, what
significance is 100o F? Or even 0o F? Nothing.
Scientists use two other scales: the Celsius and Kelvin. A Swedish
astronomer named Anders Celsius who lived in the 1700’s invented the
Celsius scale.
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The Kelvin scale was developed by a British scientist (originally from
Ireland) named Lord William Thomson Kelvin, who lived in the late 1800’s.
Another name for the Celsius scale is the Centigrade scale. This is
because there are 100 equal degrees between the freezing point of water
(at zero Celsius) and the boiling point of water (at 100 Celsius). The word
“centigrade” means “one hundredth of a degree,” just like 100 cents equals
one dollar. Most of the rest of the world uses Centigrade (or Celsius) for
weather applications.
Of course, there are conversion factors from one scale to another. For
example, to change Fahrenheit temperatures into Centigrade, use the
formula below:
o
C = 5 (o F – 32o)
9
Example
If the outside air temperature were 75 oF, we can change that to Centigrade
like this:
o
C = 5 (75o – 32o) =
9
5(43o) = (0.556)(43o) = 24o C (rounded)
9
There are some nice things about using the Centigrade scale. Since “centi“ means “hundredth”, like one cent is one-hundredth of a dollar, it is easier
to remember. Room temperature is 20o C; body temperature is 37o C.
These numbers are more rounded than the old Fahrenheit system that
most Americans have grown up with.
On the other hand, if we want to measure exact energy, the Centigrade
won’t work. Why? Because we need a scale in which zero degrees is
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exactly that – absolutely zero, where there is nothing colder anywhere in
the Universe. Scientists needed a scale that would connect energy and
temperature. And that scale is the Kelvin scale. For example, 0 K is
absolute zero. We regularly use “below zero” numbers in Fahrenheit and
in Celsius However, there are NO degrees below absolute zero. And at 0
K, there is NO energy at all, and the units are Kelvins, not degrees.
Fortunately, the size of the degree in Kelvin is the same as in Celsius; so to
change from one to the other is merely addition or a subtraction.
To change Centigrade to Kelvin, one merely adds 273:
K = oC + 273o
So, at 0o C (the freezing temperature of water), the Kelvin temperature is
273 Kelvins. Sure, that isn’t a round number either, but we really need a
scale whose lowest temperature is zero.
Although scientists did invent thermometers to measure heat, we have
known for more than 100 years that thermometers measure temperature,
not heat. One way to measure how much heat is in hot water is to
measure how long that hot water takes to melt 10 ice cubes. A gallon of
80o C water will melt 10 ice cubes much faster than a quart of 80o C water.
Also, the gallon will melt far more ice cubes in 5 minutes than the quart will.
The gallon of water has more heat than a quart of water at the same
temperature.
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Heat Transfer
One of the ways energy is transferred is by
moving heat. This is done in three ways:
1. Conduction (touch)
2. Convection (movement)
3. Radiation (heat waves)
When we touch a hot stove or hot radiator, we feel the heat immediately
on our skin. The heat energy in the stove
transfers directly to our body, if only locally,
through our skin. This is called conduction.
When we take a bath, we notice that the
warmer water may be near the faucet area,
so we use our hands to physically move the
warmer water around, in order to make the
entire bath feel about the same temperature.
This physical movement is called
convection. And when we stand in front of a
bonfire, or campfire, or roaring fireplace, we
can feel the heat from the radiation, or heat waves, coming from the fire.
The same is true if we go to the beach on a sunny day. We feel the Sun’s
heat on our skin, although we aren’t actually touching the Sun. This type of
heat transfer is also called radiation.
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The Sun radiates the planet
Earth all the time. If the Earth
kept all that energy and didn’t
let it escape into space, the
planet would burn up and even
vaporize in 27 hours! Thus,
there must be a balance, or
type of equilibrium, where the
Earth re-radiates much of that
energy back out into space.
Conductors, Insulators, and Heat Capacity
Some objects (e.g. metals) are able to transmit heat energy very well.
These are called conductors. Objects that don’t transfer heat very well
(e.g. plastics, cloth) are called insulators. Stone is in between a conductor
and an insulator. It is sometimes called a semi-conductor.
Example
Examples of conductors include most metals. Aluminum foil gets hot fast,
but also cools quickly. Examples of insulators include wood, fiberglass,
and even air. Examples of semi-conductors include ceramic, which is made
of stone. It takes stone a long time to get hot, but when it does, it holds on
to the heat and cools off slowly.
Heat Capacity, also referred to as Specific Heat, is the ability of an
element or compound to absorb and radiate heat energy.
Example
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Aluminum has a low heat capacity, which means absorbing a small amount
of heat causes a large increase in temperature. Sitting on a metal car on a
hot summer day will convince you that metal gets a lot hotter than grass
with the same amount of sunshine. But that same car in winter would be
extremely cold to sit on. Wood has a high heat capacity – it is far better as
an insulator. Thus, we have log cabins in the woods, to hold any heat
generated inside. While wood can burn, its temperature does not rise very
much on a hot, summer afternoon.
LIGHT AND SOUND
The previous lesson discussed forms of energy. Energy may be
transferred in waves, which can come in packets of light, or packets of
sound, or both.
Let’s first talk about what a
“wave” is. Imagine going to the
beach, and watching the water
come in, and go out. Each
“packet” of water is called a
wave. And perhaps one wave
comes to shore every 10
seconds or so. Each wave has a
high point, or “crest,” and a low point, or “trough.” The distance from the
crest of one wave to the crest of the next wave is called the “wavelength.”
In a typical ocean wave, that could be as much as 30 feet (about 10
meters).
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The rate at which the waves arrive is called the “frequency.” For example, if
one wave crest arrives at the shore and the next arrives 10 seconds later,
and the next arrives 10 seconds after that, etc., then, every 10 seconds a
wave arrives.
As mentioned above, then, the frequency of the wave is one divided by 10
seconds, or 1/10 per second = one-tenth of a wave per second = 0.1 /
second. This is also called 0.1 cycles per second, or 0.1 Hertz, after a
German scientist, Heinrich Rudolf Hertz, who studied waves in the late 19th
Century.
Research has shown us that the speed of a wave, “s”, is
λxv
where λ stands for the wavelength (using the Greek letter, λ) and v stands
for frequency (using the Greek letter, v).
Examples
Let’s say that the distance from
one crest to the next (the
wavelength) is 3.0 meters
(about 10 feet). Then the speed
of the wave is
Speed = wavelength x
frequency = 3.0 meters x 0.1 /
second = 0.3 m/s (about 1 foot
per second).
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One can also consider many other kinds of waves, including “waving your
hand” to say “hello” to someone. As you wave at someone, you are moving
your hand back and forth (probably left and right). Each time you do that,
you are completing one cycle.
This takes no more than about 1.0 second in most cases, so the frequency
would be one cycle per second. The length of the wave would be the
distance from the left side, to the right, and back to the left side, around 60
centimeters (about 1 foot each way, or 2 feet total). Thus, one can find the
“speed” of the wave, or how fast you are moving your hand, by using the
above relationship:
s = λ x v = 0.60 meter x 1.0 / second = 0.6 meter per second,
or 60 cm/sec (about 2 feet per second).
Both light and sound come in “wave packets,” and each has a wavelength
and a frequency. Plus, each has a speed and velocity.
The speed of light, using the symbol “c” is equal to about 300,000
kilometers per second (about 186,282 miles per second). This number is a
constant for all colors, all reference frames, and so forth. The different
colors of light all have distinct and different wavelengths with corresponding
frequencies, but all colors of light travel at the same speed.
Please do not confuse radio waves with sound waves. They are quite
different. For instance, radio waves (like light waves) travel through empty
space at 300,000 Km/s. However, sound waves cannot travel through
empty space. They travel through different materials at different speeds.
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Example
Red light has a wavelength of about 6400 Ångströms, while blue light is
much shorter, with a wavelength of about 4000 Ångströms. An Ångström is
a unit of length named in honor of a 19th Century Scandinavian scientist
named Anders Jonas Ångström. It takes 10 billion Ångströms to equal 1.0
meter! However, some scientists prefer using a different unit called a
“nanometer”. It takes 1 billion nanometers to equal 1.0 meter, so in that
sense, 1.0 nanometer = 10 Ångströms = 10 Å. So, using nanometers
instead, red would be about 640 nm and blue would be about 400 nm.
Astronomers use Ångströms while physicists (not physicians) use
nanometers.
The formula, s = λ x v can also be used for light waves. However, instead
of a speed that can change (s), we replace it with the constant speed of
light, c:
c=λxv
Since the wavelengths of light are so incredibly small, it only seems to
reason that the frequencies of light are extremely large.
As mentioned earlier, sound comes in wave packets, too. And sound has
frequencies (sometimes called “pitch”) from very high to very low. While the
speed of sound is NOT a constant, it is constant within a volume that has
the same temperature and density throughout. Why? Because sound
waves must travel through a medium, or in other words, sound must travel
through a solid, liquid, or gas. It cannot travel through a vacuum. Most of us
are used to sound traveling through air, a gas. Therefore, air is the chief
medium for sound.
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At the standard temperature and pressure (like room temperature and
regular atmospheric pressure), the speed of sound, in air, is about 342
meters per second (about 1,100 feet per second). Sound travels much
faster in a liquid, like water, and even faster in a solid, like steel.
Example
When you see a thunderstorm, first you see the bright bolt of lightning, then
you hear the awesome rumbling of thunder. Since light travels so fast, you
see the bolt of lightning almost instantly. However, you have to wait for the
sound of the thunderbolt to reach your ears, because it travels at only 342
meters per second, not at the 300 million meters per second that light does.
Therefore, if you see lightning, start counting the number of seconds (use a
stopwatch, or count, 1-Mississippi, 2-Mississippi, etc.). When you hear the
thunder from the lightning, multiply the number of seconds you counted by
342 meters (about 1100 feet). If you counted 5 seconds, then it would be
about 1 mile away (about 5500 feet). If this time span becomes shorter,
this storm is moving toward you. One good thing: if you hear the
thunderclap, the lightning bolt that caused it must have missed you,
because it is the lightning that can kill, not the thunder (no matter how loud
or scary).
Physical Science Lab
I Title: Speed of Sound
II Purpose and Theory: To study the concept, and speed, of sound.
Theory: in mechanics, the length of the wave (wavelength) multiplied by
the frequency of the wave is equal to the speed of the wave. In this case,
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the wave we are talking about is a sound wave in air. In the form of an
equation, it is:
Speed = λ x ν
where the wavelength is represented by the Greek letter, λ (pronounced
"lambda"), and the frequency is represented by the Greek letter ν
(pronounced "new"). The letter "x" in the formula stands for "multiplied by."
Sound travels the fastest in a solid, then next fastest in a liquid, and finally,
it travels slowest in a gas (air). In the depths of space where there is a
vacuum (no air or gas at all), sound does not travel. Sound waves need a
medium to travel through.
In this experiment, you will hear sounds that will grow louder or softer as
you move towards or away from them. You will also notice the farther away
you get, the more apparent it is that sound travels slower than light.
III Equipment
• 2 participants
• a noisemaking device (could be a voice, but it must be the same noise
and loudness each time)
• stopwatch
• meter or yard stick
IV Procedure
1. Find a relatively quiet street or park.
2. Mark off 100 meters in 10-meter increments or 100 yards in 10-yard
increments.
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3. Designate a “zero” point, and have your assistant stand there with the
noisemaker device.
4. Walk 10 meters or yards away and, at your signal, have your assistant
make a noise.
5. Listen carefully how loud the noise is.
6. Walk to 20 meters or yards and repeat the scenario.
7. Continue every 10 meters or yards until you reach 100 meters or yards.
8. Return to the zero point and have your assistant walk out to 10 meters
or yards.
9. Make the noise at the same time that you make a visible gesture
towards your assistant, so he or she will know that the sound went off. If
you had a starter pistol (gun), the assistant may see a plume of smoke
the instant the gun is fired, but you can be creative.
10. Start the stopwatch the instant you make the noise.
11. Instruct your assistant to raise his hand immediately upon hearing the
noise.
12. As soon as you notice his hand go up, stop the watch.
13. Do this for each 10-meter or yards increment until 100 meters or yards
has been covered.
V Data, Observations, Calculations
A. Make table of data for when you walked further away from the noise.
The first column would be “position,” from 1 to 10. The second column
would be distance, from 10 up to 100. The third column would be
sound level. Use the loudness of the sound to be equal to 1.0 at the
distance of 10. If the sound is only about half as strong at 20 than it
was at 10, put 0.5 for 20. If, however, the sound at 20 were only 1/4th
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as loud, put 0.25. Continue this all the way to the 100. If you cannot
hear any sound at any of the positions, then put zero (0.0).
B. Note if the wind is blowing and in which direction. The ideal situation
would be calm (no wind). If the wind is blowing in your direction as you
are walking away, the sound will travel farther. If the wind is blowing
towards your assistant as you walk away, the sound will not travel far.
C. Make a second table of data for when your assistant walks away,
stops, waits to listen to the noise, and puts up his/her hand. The three
columns will be position, distance, and time (from the stopwatch).
VI Results
Explain the level of success of the lab. Don’t just say “Well, it was
successful because …”. The speed of sound in normal air is about 343
meters per second, or about 1100 feet per second. If you were to see
lightning in the distance during a storm, and then counted the number of
seconds until the thunder reached your ears, you could tell how far away
the lightning bolt struck. If you wait for 5 seconds, that is about 5500 feet,
or just about one mile.
If you have the chance, try repeating the lab in a liquid, i.e., in a swimming
pool. You will notice the sound travels much faster.
VII Error Analysis
1. Personal
2. Random
3. Systematic
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VIII Questions
1. What is the value for wavelength of a sound that has a frequency of
1,000
Hz? (
= 1000 / sec). Use the value for speed of sound in VI
Results. Use metric units only.
2. Does the speed of sound depend on loudness? Why, or why not?
3. Does the speed of sound depend on AIR temperature? Why or why not?
4. What would an orchestra sound like if the higher frequencies traveled
faster (and thus got to the audience earlier) than the lower frequencies?
Key Terms and Concepts
Temperature scales of Fahrenheit, Celsius, Kelvin
Chemical burning
Heat Transfer: Conduction, Convection, and Radiation
Hydrocarbons
Heat Capacity: Conductors, Insulators, Semi-Conductors
Types of thermometers
Conversion Factors for Fahrenheit to Celsius and back
Efficiency of burning
Velocity as a function of wavelength and frequency
Wavelength
Speed of light
Frequency
Speed of sound
Speed of sound
Ångström
Hertz
Wave packet
Crest
Trough
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Problems
1. Convert 80o F into Celsius.
a) 26.7 oC
b) 62.2 oC
c) 86.4 oC
d) 201.6 oC
2. Assuming that you could burn propane 100% efficiently, what would the
end products be?
a) H2O and CO b) O2 and CO2
c) CO and CO2
d) H2O and CO2
3. If you are cold, which method is the fastest way to get warm?
a) Conduction
b) Convection
c) Radiation
d) Clothes
4. Which method does the Sun use to heat the Earth?
a) Conduction
b) Convection
c) Radiation
d) Light
5. Which has a higher heat capacity – copper or Styrofoam?
a) Copper
c) Equal
b) Styrofoam
d) NO heat capacity
6. What is the difference between hydrocarbons and carbohydrates?
a) Only carbohydrates burn
c) Only hydrocarbons have energy
d) Neither one has energy
d) Only hydrocarbons burn immediately
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7. Who was Heinrich Rudolf Hertz?
a) The first pain doctor
b) Studied sound waves
c) German scientist who studied light waves
d) Scientist who studied heat
8. Who was Anders Ångström?
a) Swedish astronomer
b) Studies temperature
c) Swiss scientist who studied light
d) Founder of Alcoholics Anonymous
9. What is the frequency of a beam of red light whose wavelength is 6000
Ångströms?
a) 0.05 Hz
b) 500 Hz
c) 50,000 Hz
d) 5 x 1014 Hz
10. What is the speed of sound at STP? (standard temperature and
pressure)
a) about 300 m/s
c) 186,000 mph
b) about 600 m/s
d) 3 x 108 m/s
11. If you see an ocean wave hit the beach every 8 seconds, what is its
frequency?
a) 0.125 Hz
b) 8 cps
c) 3.8 x 107 Hz
d) 1/8
12. How long is a typical radio wave, which has a frequency of 560 kilohertz?
a) 5.36 x 107 m
b) 560 m
c) 536 m
d) 1.8 x 10-4 m
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Answers
1. a
3. a
6. d
8. c
11. a
2. d
4. c
7. c
10. a
12. c
5. Styrofoam has a higher heat capacity than copper since it takes a long
time to warm up and doesn’t accept heat well. Copper heats up and
cools off quickly.
Choice B
9. The frequency of a beam of red light whose wavelength, λ = 6000
Ångströms, and the speed of light is a constant, c = 300,000 km/sec,
then the frequency, ν = c/ λ = 300,000 km/sec divided by 6000
Ångströms
= 50 (km/ Ångströms) per second. This is not really an
understandable answer, so we need to convert everything to meters
first. So, wavelength, λ = 6000 Angstroms = 600 nm = 6 x 10–7 meter.
The speed of light, c = 300,000 km/sec = 3 x 108 meters/sec. Thus, if ν
= c/ λ = 3 x 108 meters/sec divided by 6 x 10–7 meter = 0.5 x 1015 which
equals 5 x 1014 Hz.
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LESSON 4 THINGS TO REMEMBER
™ Styrofoam has a higher heat capacity than copper, aluminum, plastic,
or paper
™ Heinrich Rudolf Hertz was German scientist
™ Anders Angstrom was a Swedish astronomer
™ 80 degrees Fahrenheit is 27 degrees Celsius
™ Conduction is the fastest method to get warm
™ To convert Fahrenheit to Celsius (Centigrade), subtract 32 and divide
by 1.8. (Dividing by 1.8 is the same as multiplying by 5/9)
™ To convert Celsius (Centigrade) to Fahrenheit, multiply by 1.8 and
add 32. (Multiplying by 1.8 is the same as multiplying by 9/5)
™ The Sun heats the Earth by radiation
™ Heat capacity is the characteristic of a material to retain and give off
heat
™ The speed of a wave “s” is the wave length times the frequency
™ Radio waves travel through empty space at 300,000 Km/s/
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LESSON 5 - ELECTROMAGNETIC RADIATION
Electricity and its study has been around forever. In ancient Greek times,
people could rub against some objects, such as amber, and create static
electricity. Thus was born the Greek word elektron, a type of amber.
Example
If you take a balloon, blow into it to inflate it, tie it, then rub it against your
hair; it may pick up enough electrons to make it stick to a nearby wall. This
is because the balloon becomes negative and attracts the positive particles
in the wall. If you live in a very humid part of the country, this does not work
very well. The water particles in the humid air also attract the electrons.
However, as you remove dried clothes from electric clothes dryer (definitely
NOT humid air) you may have noticed socks sticking to shirts. When you
peel the sock from the shirt and hold it near your arm, it attracts your hair.
The understanding, and measuring of electricity,
however, didn’t start seriously until the 18th
Century. One of the best-known early scientists to
study it was America’s Benjamin Franklin. His
studies in electricity – static electricity – spanned
the years of approximately 1747 – 1752. During
the late 1770’s and the 1780’s, a French scientist named Charles Augustin
de Coulomb studied electricity and magnetism.
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Essentially, electricity is all about electrons,
those tiny subatomic particles with a
negative charge. When a whole bunch of
electrons are together on a surface but
they are not moving, this is called static
electricity. When electrons move along a
wire, it is called electric current. These terms make sense, since static
means “no change” or “not moving,” while current is like the continued
movement and flow of water in a river.
Example
You plug in an electric appliance, such as a radio, television, or lamp, and
then turn it on. Then electrons flow into and out of the device, as water in a
river flows into a lake and then out of the lake into another river.
There are subatomic particles called “protons.” While each of these
subatomic particles is about 1,800 times heavier than each electron, a
proton has a single positive charge. An electron has a single negative
charge. They are equal and opposite. Nature is so amazing!
Coulomb determined that each electron, and each proton, has a distinct
amount of charge. Because he developed the unit of charge, its name is
the “Coulomb.” One Coulomb of charge has all of the charges of about 6.24
x 1018 electrons (negative charge) or 6.24 x 1018 protons (positive charge).
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Example
If you wanted to write out the total number of electrons in one Coulomb of
charge, it would be 6,240,000,000,000,000,000 electrons! Therefore, each
electron has a negative charge of about 1.60 x 10-19 Coulomb. Each proton
has a positive charge of about 1.60 x 10-19 Coulomb.
The current in electrical current means how many electrons pass a certain
point in a second of time. This is called the Ampère, and is equal to 1.0
Coulomb per second. This name honors another French scientist, André
Marie Ampère, who studied electricity during the early 1800’s.
Electromagnetic radiation is a ten-syllable word for energy that
always travels through empty space at 300 million meters/second. We call
the visible portion of the energy light.
Example
Our eyes can detect seven
distinct colors: red, orange,
yellow, green, blue, indigo, and
violet (ROYGBIV). We call these
7 colors the “visible” spectrum, or
the range of electromagnetic
energy that can be seen by
humans. Each of these colors
also has a range, or spectrum.
Each color blends into the next
color to form the familiar rainbow.
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Most of the Sun’s electromagnetic
energy is in this range. But, the visible
“range” is so small compared to all of
electromagnetic energy. This means
that humans cannot see most of the
electromagnetic energy spectrum, but
only the small range of visible light.
Example
The 7 colors of the rainbow (ROYGBIV) range from about 4000 Å to 6400
Å in wavelength (or 400 nm to 640 nm). However, the entire
electromagnetic spectrum has a range tens of thousands of nm greater.
Among the visible colors, red is the “weakest,”. It
has the longest wavelength and the smallest
frequency. The German scientist Max Planck
determined that the energy of a wave packet of
light is equal to a constant multiplied by the
frequency of that light: E = h ν
Where E is the energy in Joules, “h” is a constant that Planck was able to
determine experimentally (and is equal to 6.6 x 10-34 Joules/Hertz
= 4.136 x 10-15 electron Volt seconds), and ν is the frequency in Hertz. In
his honor, we call the constant, “h,” Planck’s constant.
So, as far as visible light is concerned, violet is the most energetic.
However, what is below red and what is beyond violet? Those
wavelengths that are longer than red, and thus, have a lower energy, are
called “infrared.” This means “below red.” Stars that are cooler than the
Sun give off infrared (IR). We humans also give off infrared energy (heat).
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Example
Some people have tried to make everyone believe that there are black
people, white people, yellow people, and red
people. While the skin’s reflectivity varies from
person to person, all people give off the same
frequency of infrared waves. Those with fevers
may have a slightly different frequency of infrared,
and dead people are the same temperature as
their environment. People are not “black,”
although there are dark-skinned people. In the
same way, there are no “white” people either,
although albino people are close. In essence, skin
color is an environmental adaptation.
Another example of electromagnetic radiation is microwave radiation, a
type of energy used both for communications and for warming food.
Finally, we reach radio electromagnetic energy. Some forms of radio
energy have wavelengths of more than a kilometer (more than 5/8 mile).
Both television and radio stations use forms of radio energy to transmit
their signals. They do not transmit sound waves.
Example
A radio station on the “AM dial” with a frequency of 1200
kHz has a wavelength of 250 m. Another station, on the
“FM dial,” with a frequency of 95 MHz, has a wavelength of
3.15 m. We find this using λ x ν = c = 300,000,000 m/s.
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Wavelengths that are shorter than violet, and have a higher frequency and
higher energy, are called “ultraviolet,” meaning “beyond violet.” The Sun
does give off quite a bit of ultraviolet light. This results in humans getting
sunburned, or some kind of skin cancer. Most stars also give off quite a bit
of ultraviolet light.
Next along the spectrum is the higher
electromagnetic energy called “x-ray.” The
German scientist Wilhelm Roentgen discovered
this energy accidentally in 1895. Medical students
must take at least one course about x-ray
technology, and it’s called “roentgenology.” When
people need to get an x-ray for possible broken bones, ruptured disks, or
decaying teeth, they must “pose” for an x-ray photo. A few stars give off xrays – they are usually the brightest, hottest stars, or they may be part of a
star system with a mysterious star called a “black hole.”
Example
The next time that you are at your doctor or dentist’s office, ask if you can
see an image of your most recent x-rays.
The most energetic of all electromagnetic energy, and the one with the
shortest wavelengths, is called “gamma ray.” These are most dangerous.
Gamma rays are given off in nuclear explosions, and they also radiate from
the centers of galaxies. Even a short exposure to gamma rays will cause
death in about 41 minutes.
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Astronomers are scientists
that study the stars. One way
that they can study the stars
is by “gathering” their light,
with a “light funnel,” or
telescope, such as at an
observatory. Then they
examine the electromagnetic
energies from those stars. They use special cameras to make permanent
records of the starlight. A biologist may bring in a specimen and examine a
plant or animal up close in a lab. However, astronomers cannot pull a star
in for close observation, nor can they travel to the stars to study them, at
least not yet.
Key Terms and Concepts
static electricity
gamma rays
x-rays
electric current
radio waves
microwaves
Energy
visible spectrum of light
Power
electromagnetic radiation
Problems
1. How many electrons are in 1.0 Coulomb of charge?
a) 1
b) 6.02 x 1023
c) 6.24 x 1018
d) 20
2. How much heavier is the proton compared to the electron?
a) 6.02 x 1024 times
b) 1800 times
c) twice
d) equal
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3. What kind of electricity did Benjamin Franklin study?
a) static
b) household
c) battery
d) conducting
4. How many colors are in the rainbow?
a) eight
b) infinite
c) three
d) seven
5. How many regions of the electromagnetic spectrum are there outside
the rainbow?
a) one
b) three
c) six
d) infinite
6. Which is the most energetic electromagnetic radiation?
a) gamma
b) radio
c) UV
d) X-ray
7. What kind of charge do electrons have?
a) positive
b) neutral
c) revolving
d) negative
c) the Ampere
d) Visa
8. What is the basic unit of charge?
a) the Coulomb b) the Watt
9. What is the basic unit of electrical current?
a) Volt
b) Ampere
c) Watt
d) Coulomb
10. What are the longest wavelengths of electromagnetic radiation?
a) infra-red
b) ultra-violet
c) radio
d) X-ray
Answers
1. c
2. b
3. a
4. d
7. d
8. a
9. b
10. c
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6. a
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LESSON 5 THINGS TO REMEMBER
™
One Coulomb of charge has 6.24 x 10 18 electrons, or 6,240,000 trillion
™
A proton is 1,800 times heavier than an electron
™
Ben Franklin studied static electricity
™
Teal is not a color of the rainbow
™
Gamma rays are the most energetic electromagnetic radiation
™
There are 6 colors outside the rainbow
™
5.0 Coulombs of electrons flowing past the middle of a copper wire in
.10 seconds, then the electric current in that wire is 50 amps
™
A wave of electromagnetic radiation has more energy if it has higher
frequency
™
In a nuclear explosion, the most dangerous type of energy is gamma
rays
™
Astronomers cannot bring what they study into the lab
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LESSON 6 - BUILDING BLOCKS and NUCLEAR ENERGY
Scientists in ancient Greece proposed the existence of a “building block
particle” called atomos meaning “indivisible.” Scientists have learned that
atoms are not indivisible but are made of smaller particles such as protons,
electrons, neutrons, and others.
For thousands of years, scientists have accepted the concept of tiny
particles combining in some fashion to create everything. However, only in
the past two hundred years have they understood the design and function
of atoms.
Scientists identified elements, one at a time, as history moved along. Their
exact make-up initially was nothing more than educated guessing. Later, a
variety of experiments and tests confirmed or denied the theories.
Two things make up all atoms, like this
atom of helium: the nucleus, and any
Electron
0.05 mr
Nucleus
electrons that are, in some way,
traveling around it. The nucleus
essentially contains two types of
particles: protons and neutrons.
Hydrogen is the only element that has
no neutron in the nucleus of any of its
atoms.
The first model of an atom looked like the Sun, with planets orbiting around
it; or a large planet with many moons orbiting around it. In this way, the
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nucleus, or core, is like the big heavy object in the middle. The electrons
are the much smaller, lighter objects orbiting around the nucleus.
Anything smaller than the atom is, by definition, sub-atomic; since atoms
are made of electrons, protons, and neutrons, all three are sub-atomic
particles. The word “proton” comes from the Greek word proton, which
means “first one.” The word “neutron” comes from the Greek word,
neutron, which means “neutral one.” There are also some other quite
unusual and even smaller subatomic particles.
The atoms of some elements do not
combine with anything else. We call
these elements the “Noble Gases”.
However, with the exception of the
Noble Gas family, atoms of all
elements combine with one or more
atoms of other elements.
Sometimes an atom of one element
will combine with another atom of
the same element (just like itself), as mentioned next.
Combinations of atoms are called “molecules,” from the Latin word moles
that means “little mass.” Some molecules are simple combinations of two
atoms of the same element, such as hydrogen gas (H2). Other molecules
like that include oxygen gas, O2, nitrogen gas, N2, and so forth. More
complex combinations of atoms include molecules of two or more different
elements. Examples include carbon monoxide, CO; hydrogen chloride,
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HCl; table salt, NaCl; and even the large molecule of glucose, C6H12O6,
which has six carbons, 12 hydrogens, and 6 oxygens.
Molecules are quite small, and, obviously, atoms are smaller yet.
Subatomic particles are so small that they can’t be seen at all. We can do
experiments to prove that electrons and other subatomic particles exist.
However, we can’t merely shine a light on, say, an electron and ask it to
stay still so we can photograph it. In fact, any light that we could shine on
an electron would give it a huge boost of energy. It would take off like a
shot – close to the speed of light itself! So, we would never really know
where it was.
All the elements that exist in the universe come from only one element –
and that is the most abundant element in all of space: hydrogen. Henry
Cavendish confirmed this first element in 1766. The word is from the Greek
“hydro” and “genes” which means the “forming agent of water.”
The first and lightest element, hydrogen, is the primary building block for all
other elements. In the high temperatures and pressures of the cores of
stars, four atoms of hydrogen joined together (fused) to make one atom of
the next heaviest element, helium, then went on to build other elements.
Example
All stars are made of hydrogen gas. After a while, much of the hydrogen
gas turns into helium, and then to carbon, and then to iron, and various
other byproducts.
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Here is how it is done:
4 H = He + 2β+ + Energy
where the energy is [(Δm)c2] and where 4 hydrogen nuclei, through several
reactions, create one helium nucleus. This reaction also gives off two very
+
small, positive particles called “beta” particles. (β ). They are really positive
electrons. The reaction gives off a great deal of energy.
Recall that “Einstein’s Equation” usually is written
E = mc2
to show
how much nuclear energy is produced when subatomic particles seem to
disappear in nuclear reactions. Because actually a very little amount of
matter (mass) becomes energy, this equation SHOULD BE written:
E = Δmc2. This is actually the chemical formula for the explosion of a
hydrogen bomb. At the center of every star, the equivalent of untold
numbers of hydrogen bombs are going off each second.
However, there is one very interesting event here. The mass of 4 hydrogen
nuclei is greater than the mass of one helium nucleus. And the two beta
particles are the same very low weight as electrons. So, how can we
physically balance this formula if there is some mass that “disappears”? In
reality, it doesn’t disappear. Instead, the missing mass is converted
entirely into energy. The missing mass, or Δm, when multiplied by the
square of the speed of light (c2) gives an answer in the units of Newtonmeters, or Joules. Thus, stars are nuclear furnaces that create heavier
elements. In the Physical Sciences, we use the capital Greek letter Delta
(Δ) to indicate difference or change. So, missing mass is Δ m.
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Example
Our Sun is “losing” mass at the rate of about 600 million tons per second.
It has been doing this for 5 billion years with little noticeable effect. And
every second, matter that would weigh 600 million tons is completely
converted into pure energy.
As an example, if we could “convert” 1.0 kilogram of matter (about 2
pounds) into pure energy every second, what power would that create?
Let’s work it out:
E = (Δm)c2
where (Δm) = 1.0 kilogram, and c = 300,000 km/sec = 300 million m/sec.
And this would then be 300 million joules/sec or 300 million watts of power
= 300,000 kilowatts of power. That’s enough power to run a small city for a
week! And, to a good extent, that is what we do when we use nuclear
power plants.
After a while, helium begins to turn into carbon, by this reaction:
3 He = C + Energy
and much later, carbon is fused into iron:
3 C = Fe + Energy
and so forth.
Nuclear bombs began with the first atomic bombs developed at the end of
World War II. After that war, scientists looked for a way to harness this
massive energy for peaceful uses, such as providing electricity to homes
and businesses. However, one can’t make a bomb go off slowly, so they
searched for other elements to use.
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Atomic bombs, such as the hydrogen bomb, are fusion reactions. This
means that they take several smaller elements and make one larger
element, as mentioned earlier:
4 1H1 = 2He4 + 2β+ + E
Four hydrogen nuclei are fused together, in a chain reaction process to
form one heavier helium nucleus.
In trying to design a nuclear energy power plant, one needs to be able to
control the release of energy over a long period of time, rather than all at
once. The way to do this, scientists found, was through nuclear fission.
This reaction is just the opposite of fusion. Instead of fusing smaller
elements into larger ones, fission takes very heavy elements and splits
them into smaller elements. In some cases, fission also releases a great
deal of energy.
Example
One popular type of fuel used in fission processes is Uranium, which is
naturally occurring inside Earth. Every atom of Uranium has 92 protons, all
of them in the atom’s nucleus. Like many elements, Uranium has several
“isotopes” (different versions of the element). For example, U-235 is an
atom of Uranium that has 143 neutrons in the nucleus. Another isotope, U238, has 3 more neutrons in the nucleus.
U-238 is much more abundant in nature than U-235. However, it is rather
easy to split the U-235 nucleus to get the energy out, and it is very difficult
to split the U-238 nucleus.
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In the fission reaction with U-235, the nucleus is bombarded with a
neutron, and the nucleus splits into two smaller elements, Barium and
Krypton.
It also gives off about 200 Million Electron Volts (200 MeV) that can be
used peacefully to power homes and businesses. As an example, 1.0
kilogram (about 2 pounds) of U-235 can yield 18.7 million kilowatt-hours of
energy.
Example
Because the amount of U-235 on Earth is limited, scientists have found a
way to use the much more abundant U-238. In this new reaction, a neutron
is fired at the U-238 nucleus. Since U-238 will not split apart, it actually
absorbs the neutron, making a new isotope of Uranium, called U-239. The
U-239 nucleus is unstable, and will spontaneously change one of the
neutrons into a proton. Then it will give off a “positron” (a positive electron,
called a beta particle), thus changing the element itself from Uranium to
Neptunium. A short time later, a neutron in the nucleus of Neptunium will
change into a proton. It will give off another positron, thus changing it to
another element, Plutonium.
Note that while all isotopes of Uranium have 92 protons in the nucleus,
Neptunium has 93 protons and Plutonium has 94 protons.
Now that we have Plutonium-239, this new end product can be split into
smaller elements and give off energy, just as U-235. This type of multiple
reaction sequence is called a “breeder reaction”. It occurs in a more
advanced type of nuclear power plant called a “breeder reactor.”
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There are safety concerns in all types of nuclear reactors. However,
technology is improving at such a rate that future problems will be almost
non-existent. And the fuel supply for a U-238 to Plutonium breeder reactor
is almost inexhaustible.
Key Terms and Concepts
Atoms
breeder reactor
nucleus
Molecules
creation of heavy elements stellar reactions
Protons
atomic fission
hydrogen fusion
Electrons
atomic fusion
helium fusion
Neutrons
carbon fusion
hydrogen fusion
creation of subatomic particles
Problems
1. How many electrons are in a neutral A) hydrogen atom? B) Lead
atom?
A) a) 0
b) 1
c) 2
d) 4
B) a) 0
b) 60
c) 82
d) 125
2. How many neutrons are in a neutral
A) hydrogen atom? B) Lead
atom?
A) a) 0
b) 1
c) 2
d)
4
B) a) 0
b) 60
c) 82
d) 125
3. What is the proton-proton reaction to create helium from hydrogen?
a) 4 1H1 = 2He4 + 2 β+ + energy
b) 1H1 + 1H1 =
c) 1H1 + 1H1 =
d) 4 1H1 = 2He4 + energy
2He
2
+ energy
2
2H
+ energy
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4. How are the heavier and more complex elements made?
a) Explosion of an atomic bomb
b) Decomposition of Uranium
c) By heat deep within the Earth
d) One element at a time, by smaller elements joining together
5. What are positrons?
a) positive neutrons
c) negative protons
b) positive electrons
d) negative electrons
6. How does matter turn into energy, using Einstein’s formula?
a) E = Δmc2
b) E = Δmc
c) E = mΔc
d) E = m2Δc
7. According to the following equation,
92U
235
+ 0n1 =
56Ba
+
36Kr
+ energy
a) After being bombarded by a neutron, U-235 nuclei split into Barium
and Krypton nuclei plus energy.
b) When a lot of energy goes into the nucleus of U-235, it breaks apart
into Barium and Krypton nuclei.
c) Nuclei of Barium and Krypton fuse together to make nuclei of Uranium
and much energy.
d) Energy breaks up into Krypton and Barium.
8. How many atoms of hydrogen are needed to create 1 atom of helium?
a) 1
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b) 2
c) 3
d) 4
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9. Which Uranium is used to create the breeder reactor?
a) U-235
b) U-236
c) U-237
d) U-238
10. Atoms of different isotopes of the same element ______________.
a) Have different numbers of protons in their nuclei
b) Have the same numbers of neutrons in their nuclei
c) Have the same number of electrons in their nuclei.
d) Have different numbers of neutrons in their nuclei.
Answers
1. A) b
B) c
4. d
7. a
2. A) a
B) d
5. b
8. d
6. a
9. d
3. a
10. d
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LESSON 6 THINGS TO REMEMBER
™ There is 1 electron in a neutral hydrogen atom
™ There are 0 neutrons in almost all neutral hydrogen atoms
™ Positrons are positive electrons
™ 4 atoms of hydrogen are needed to create one atom of helium
™ U238 is the Uranium needed to create the breeder reactor
™ Heavier and more complex elements are made one at a time from the
fusion of atoms of hydrogen, helium, and heavier elements
™ Einstein’s formula says that Energy is equal to the mass of the matter
that is lost times the speed of light squared
™ Ne does not represent one molecule of a substance
™ Producing electric power with a nuclear reactor produces several
nuclear fission reactions
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LESSON 7 - CHEMICAL ELEMENTS
There are over 100 elements, from hydrogen to uranium, and beyond.
While hydrogen is the most abundant element in the universe, it is certainly
not available on Earth in very high quantities! In fact, there is a huge
abundance of iron, nitrogen, oxygen, and silicon on Earth, but very little
hydrogen.
Scientists discovered more and more elements. They decided to arrange
these elements into some sort of table. Then they looked for things that the
elements may have in common with each other. Eventually, the Periodic
Table of Elements was created.
The Periodic Table had a number of scientists who
contributed to it. The actual Periodic Table was developed
by a scientist named Johannes Periodic – no, just kidding!
The real scientist was a 19th Century Russian chemist
named Dmitry Mendeleyev. He determined the “Periodic
Law of Elements”. This states, “Elements show a regular pattern of
properties when they are arranged according to atomic weight.” We call
this regular pattern “periodicity.” Mendeleyev developed the first Periodic
Table in 1869, and his second draft came out in 1871. It has been evolving
ever since.
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Source: http://www.wisegorilla.com/images/chemstry/periodic_table_of_elements.jpg, 01/19/2006.
As one can see, the Periodic Table puts the elements in order, from left to
right. The number at the top of each box (the “atomic number”) is the
number of protons in the nucleus of each atom of the element. The very
first element, hydrogen, has only 1 proton. Uranium has 92 protons, so it is
much further down.
The elements in the right-hand column, known as the Noble Gases, have
all of their electrons spaces filled. Isotopes of elements are just different
versions of the atom, having the same number of protons, but differing
numbers of neutrons. The word, “iso” means “equal” or “the same” and
refers to the number of protons in the atom’s nucleus. It is the number of
protons that tells one what element it is, no matter how many electrons or
neutrons the atom may have.
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Example
The lightest element, with the lowest number of protons is the gas
hydrogen. It has only one proton in each atom. In its most common and
most stable state, almost all atoms of this element also have one electron
each – but no neutrons. Therefore, the most common isotope of hydrogen
has no neutrons. However, “deuterium” is an isotope of hydrogen with one
neutron in each atom’s nucleus. Another, called “tritium”, has two
neutrons. These are most rare, and when they are not involved in some
nuclear reaction, they quickly decay to the common hydrogen. Water is a
combination of hydrogen and oxygen in the form of H2O. It can be made
with hydrogen in the form or deuterium OR tritium. Nuclear scientists call
this “heavy water”.
The second element, helium, is also quite rare on Earth. However, it is the
second most abundant element in stars, and, in fact, in the whole universe.
Helium has two protons in the nucleus of each atom. In its most common
isotope, it has two neutrons. “Light helium” is another isotope, having only
one neutron in each atom’s nucleus. This sounds strange, as helium is
lighter than air already. You use it to inflate party balloons.
The Periodic Table continues to put into categories each and every
element, including carbon, silicon, oxygen, sodium, copper, silver, gold,
uranium, and many others. There are about 100 “natural” elements, and
many more that scientists created to study the nuclear process. Most of the
elements made by scientists decay quickly (they fall apart into lighter
elements) and don’t have a long life.
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Isotopes and Radioactivity
As mentioned, an isotope is a version of an element. There may be two or
more versions, or isotopes, for an element. Typically each element has a
“stable” isotope that doesn’t change over time. But there are other isotopes
of natural elements that break down and decay spontaneously into lighter
elements. In some cases, this may take seconds, or fractions of seconds;
in other cases, it may take billions of years to decay. Isotopes that decay
all by themselves over time are called radioactive.
Example
After a period of time has passed which called a radioactive isotope’s “half
life”, there is only half of the original material remaining. Then, after another
half-life has passed, one-half of what was left has now decayed. Thus, after
two half lives, one half of one half (one-fourth) of the original remains.
Some common radioactive elements include Radium, which decays to half
its original amount in just about 1,622 years. Uranium-238 takes about 4.6
billion years before an original amount decays to about half of what it was.
In essence, some elements never decay completely, because too much
time must pass for all of it to be gone.
Isotopes are radioactive not merely because they break down into lighter
elements. It is not unusual for radioactive decay to produce positrons,
neutrons, neutrinos (very small particles similar to neutrons), alpha
particles (these are the nuclei of helium atoms) and other high-energy, fastmoving particles. Being near such radioactive materials for an extended
period is dangerous. They travel right through the body. They can
seriously damage cells in the body, as x-rays do.
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Example
Up until the mid 1960’s, it was popular to buy a wristwatch with a radium
dial. The dial would glow in the dark all the time. Modern watches have
phosphorescent paint that absorbs light, then glow in the dark for a while.
However, radium dials glow all the time. It has nothing to do with outside
light. The people who worked in watch factories were beginning to die of
cancer and other diseases. Therefore, there are no longer any radium dial
watches.
Each element is built from elements with fewer protons in each atom’s
nucleus. This extends all the way back to the main building block.
Hydrogen’s atomic number (1) means 1 proton in the nucleus of each
atom. And the list of all of these elements is the Periodic Table. However,
the Periodic Table provides much more information. For example, you will
find the number of protons, electrons, neutrons, and the chemical formulae
for the isotopes. In many cases, you will see the atomic structure, too. Plus,
you are given the mass of 1.0 mole of the element’s combined isotope
average. This is often called the atomic mass, given in Atomic Mass Units
or AMU.
The unit 1.0 mole is a large number. While the unit “1.0 dozen” is equal to
the number 12, the unit 1.0 mole is equal to the number 6.02 x 1023. That
would be 602 followed by 21 more zeroes! So, for example, 1.0 mole of
hydrogen atoms has a mass of about 1.0 gram. Also 1.0 mole (6.02 x 1023)
of carbon atoms has a mass of about 12.0 grams. Therefore the mass of
EACH carbon atom is 12.0 grams divided by 6.02 x 1023 or 2 x 10 -23
grams. This is 0.00000000000000000000002 grams. These atomic
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masses (1 AMU, 12 AMU) are written near the element’s symbol in the
Periodic Table, which may be found in most full-sized dictionaries.
THE ELEMENT CARBON
Carbon is just about the most important element in the universe. The study
of carbon and its association with life is called “organic chemistry,” because
life forms have one, or more, organs.
Oxygen, hydrogen, and other elements are also critical. ALL life on Earth is
the same, and it is because of carbon. In fact, it is most likely that any and
all life forms anywhere in the universe and in the multiverse are carbonbased!
For whatever reason, carbon is the
Electrons
only element that can combine with
itself to make very long chains and
complex molecules. For life to exist,
large, complex molecules are
Nucleus
(800 times
actual size)
necessary.
Coal, a common source of fuel, is
mostly carbon. But if coal is heated under pressure, given enough time, it
will form diamonds because a diamond is pure crystalline carbon. And who
would want to burn diamonds?
The formation process for natural diamonds is very complex. We know that
coal is made out of what used to be plants. These plants became buried in
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Earth’s soil – some as long as 290 million years ago. Long, long ago, there
were tropical swamps in parts of Earth that are no longer there. Green
vegetation flourished in these murky areas.
Generations of these plants died and then settled to the bottom of the
swamps that they were in. Over a long period of time, the organic stuff
released their gases of oxygen and hydrogen. The remaining material was
mostly carbon.
In this long process, many layers of mud and sand built up, covering the
rotting plant parts. This squeezed the organic material more and more until
it became solid. Before the decomposing vegetation turned into coal, the
plant material became a dark brown, heavy organic goo known as peat.
Many cultures use peat as a fuel source because it burns when dried.
However, it is low in carbon and high in moisture compared to coal. Thus,
peat is not as good a fuel as coal.
During millions of years, deeper layers over the peat exerted a great deal of
heat and tremendous pressure on the stuff below. This eventually became
coal. Europe (mostly of what used to be the Soviet Union) has about 44%
of the coal reserves on Earth. North America (mostly the United States) has
about 28%.
With continued heat and pressure over time, the coal is compressed into
crystalline carbon, or diamond. Oddly enough, while less than 5% of the
world’s coal is in Africa, most of the diamonds are there. Interestingly, one
day back in 1866, a boy was walking along the Orange River in South
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Africa. He spotted a very pretty stone on the riverbank. It turned out to be a
21-carat diamond, and the rush was on. A similar “rush” occurred in 1989 in
northwestern Canada.
It is also interesting to note that a number of meteorites from space have
had diamonds inside them. However, they are slightly different than Earth
diamonds.
In the Periodic Table, a vertical
column of elements is called a
“family”. Other atoms that are in the
same “family” as carbon include
silicon, germanium, tin, and lead.
However, try as they might,
scientists have never been able to
repeat the chain-building
characteristic of carbon. Silicon can
form up to 7 bonds in a link, but then it falls apart. The 1960’s television
series, “Star Trek,” suggested that silicon life forms could exist. (Rocks and
stone have a lot of silicon in them, in the form of silicate). In one episode,
Dr. “Bones” McCoy was able to “heal” a rock creature by filling its wound
with cement! The remaining members of the carbon family don’t even do
as well as silicon.
We, as humans, are a carbon-based life form, and so are all mammals, and
all plants. In fact, all life forms have the same chemical orientation.
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In chemical terms, we often hear the words compound, mixture, and
aggregate. Defining these terms is quite easy, actually.
A “compound” is a particle that has two or more atoms of different
elements. If one has an amount of some pure compound, such as sugar or
salt, that is also called a “substance.”
“Mixtures” are combinations of two or more
separate compounds. Examples include
wood, milk, concrete, and so forth. By
examining them carefully, one can see the
separate compounds. Milk is made of water,
calcium lactate, and lipids (fats). Concrete
has sand, rock, limestone, and other
ingredients. Chemists call these
“heterogeneous” mixtures.
There are also “homogeneous” mixtures. One or more of the compounds
dissolves into one of the other compounds. Chemists call the compound
that dissolves the “solute.” They call the compound that causes the other
to dissolve the “solvent.” An example would be salt and water. When you
add salt to water, it dissolves, and the mixture becomes salt water. In this
case, the salt is the solute, and water is the solvent. When the solute
dissolves into the solvent, the resulting mixture is called a “solution.”
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Typically, it is called a solution when the particles of the solute are smaller
than 10 Å (or 1.0 nm or 10-9 meters).
Example
What about larger particles in an alleged solvent? If the particles are larger
than 1000 Å (100 nm) in diameter, most likely they will “settle out”. They will
fall to the bottom, like chocolate powder in milk or like the ingredients in
Italian salad dressing. In order to use these products, we always have to
“shake well” before use. Particles that are too large to dissolve end up
being suspended in the solvent. Eventually they settle to the bottom, pulled
by gravity (assuming the particles are denser than the solvent), like fine
grains of sand in a glass of water. A mixture of such a solvent and such
larger particles is called a “suspension,” and it’s a type of “aggregate.”
There is also a middle type of mixture that is neither a solution nor a
suspension. When particles are approximately between 10 Å and 1000 Å
(1.0 nm and 100 nm), they don’t really dissolve, but they don’t really settle
out, either. They are sort of permanently suspended, and they are given a
special name, called “colloidal suspensions,” or simply a colloid.
Many of the newer brands of food supplements are sold but as colloidal
suspensions. The body digests them much more easily. As our bodies age,
it becomes more difficult for them to digest vitamins, minerals, herbs, and
other pills. Thus, by grinding up the minerals into very small sizes in which
they are actually in a state of colloidal suspension, the body will more
readily absorb them. Thus, they will do the body more good.
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Example
Fill a glass with water, and add sand. Repeat with other small items. See if
they are solutions or suspensions.
Key Terms and Concepts
Mole
mixture
compound
Isotope
aggregate
solution
Element
colloidal suspension
solvent
Radioactivity
solute
the carbon “family”
half life
coal and diamonds
tritium
deuterium
atomic mass unit, or AMU
stories from fiction (StarTrek, StarWars)
heterogeneous and homogeneous
Problems
1. How many atoms are in a mole of Helium gas?
a) 1
b) 2
c) 100
d) 6.02 x 1023
c) 12.0
d) 6.02 x 1023
2. What is the AMU of Carbon?
a) 1.0
b) 2.0
3. Isotopes are atoms of the same element having different numbers of:
a) protons b) neutrons
c) electrons
d) atomic numbers
4. If you started with 1000 grams of radium, how many grams would be left
after three half-lives?
a) 500 g
100
b) 250 g
c) 125 g
d) 62.5 g
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5. Who created the Periodic Table?
a) Hertz
b) Angstrom
c) Franklin
d) Mendeleyev
6. Imagine that you want to get married, but cannot afford a diamond ring.
Would it be a good idea to get a ring with coal on it? Why or why not?
a) Yes. It is cheap and you can clean the coal off of it.
b) No. You cannot squeeze the coal to become diamond fast enough.
c) Yes. She will be thankful at her wedding for any ring.
d) Yes. You can burn the coal to warm your cold, cold heart.
7. Diamond is produced naturally in which one of the following sequences?
a) Diamond, rotting plants, peat, coal
b) Peat, rotting plants, coal, diamond
c) Coal, peat, diamond, rotting plants
d) Rotting plants, peat, coal, diamond
8. What was discovered in 1866?
a) Oil leaking out of the ground
c) Gold
b) A large diamond in a river bank
d) Uranium
9. What is the name of the fictional stone creature in Star Trek?
a) Stony
b) Spock
c) Horta
d) Bones
10. Mining for diamonds in South Africa is one way to get diamonds. What
is another, “other world” way to do it?
a) Visit Neptune tomorrow
c) Watch Star Trek
b) Pick up meteorites here
d) Crush coal
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11. The desalination of seawater (removing salt from salt water) requires:
a) Fish
b) Light
c) Ice
d) Heat
12. “Shake before using” salad dressing is a(n):
a) Mixture
b) Solution
c) Compound
d) Aggregate
13. Is concrete heterogeneous or homogeneous? Explain.
a) Heterogeneous, because you can see what makes it up.
b) Homogeneous, because you can see what makes it up.
c) Homogeneous, because you cannot see what makes it up.
d) Heterogeneous, because you cannot see what makes it up.
14. What is the most efficient way to ingest minerals?
a) A suppository
b) An injection
c) Chew well.
d) Swallow a colloidal suspension
Answers
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1. d
4. c
7. d
10. b
13. a
2. c
5. d
8. b
11. d
14. d
3. b
6. b
9. c
12. a
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LESSON 7 THINGS TO REMEMBER
™ There are 6 x 10 23 power atoms in a mole of Helium gas
™ 12 is the AMU of Carbon
™ An isotope is a version of an element
™ Starting with 1,000 grams of radium, there would be 125 grams left after
3 half lives.
™ Mendeleyev created the Periodic Table
™ Removing salt from seawater is called desalination
™ Horta is the name of the fictional stone creature in the TV series Star
Trek
™ Concrete is said to be heterogeneous
™ Before becoming a diamond, coal must become the following first:
rotting plants, peat, coal and then diamond
™ In a solution, the solute particles are the smallest
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LESSON 8 - CHEMICAL CHANGE
In this section, you will learn about how things change chemically. In
essence, there are three kinds of changes: physical, chemical, and nuclear.
An example of a physical change
would be to take a piece of paper
and tear it. Now it is no longer a
large piece of paper. Now there
are two smaller pieces of paper.
But they are still paper. That has
not changed.
Example
Another example would be to take liquid
water, and put it in the freezer. After a while,
it will expand and become very hard – it will
turn into a new solid called “ice.” However, it
is still water, but just in a different state. Or
you can take water and put it in a pot on the
stove. Bring it to boil. Eventually, all the
water will be gone! But the water has not
disappeared, nor become something else. It
has become water vapor. It is still water, but
just in a different form.
All of the above deal with physical changes. In Lesson 6, we learned about
nuclear changes. This occurs when we are changing one element into a
completely different element. For example, changing hydrogen into helium,
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by fusing 4 hydrogen nuclei (4 protons) into a new helium nucleus
(containing 2 protons). There is no longer any hydrogen.
Chemical changes occur when two or more atoms form a third substance
or perhaps several new substances, or when one or more molecules
change to form one or more new molecules.
Example
An example of chemical change would be to take the paper that was torn
and light the paper on fire with a match. As the paper burns, it changes
into other substances – water vapor,
carbon dioxide, and other things. After it
is all burned up, it is no longer paper.
There may be some ashes left over, but
ashes are not paper; tearing a piece of
paper won’t change the fact that it is still
paper. But burning paper will destroy
whatever paper there was, and change it into one or more other things. The
burning paper also likely will catch on fire your clothes, paper plates/towels,
carpets, grease, oil.
Example
Chemical change is also true with gasoline. It has a chemical formula of
C8H18, and when it is burned, or oxidized, by combining it with oxygen the
equation is:
2 C8H18 + 25 O2 = 16 CO2 + 18 H2O
+ Energy
You do not end up with gasoline. The new substance(s) cannot behave like
gasoline.
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Example
Some reactions are reversible because you can get back what you started
with. It is not possible to combine water and carbon dioxide to create
gasoline and free oxygen. However, water’s formation process can be
reversed to produce hydrogen and oxygen gasses by passing an electric
current through the water:
2 H2O + Energy = 2H2 + O2
This process is called electrolysis. Do not confuse it with hydrox, which is
a brand of cookie similar to Oreos.
In summary, we have chemical change when one or more items change
into other items and some are reversible.
If you have gotten this far, you have already come across a number of
chemical equations. These are different from math or physics formulae.
They deal with the correct amounts, or ratios, of atoms or molecules on
both sides of an equation. On the left side of the equation are the reactants,
those substances that will react together to become something else. On the
right side of the equation are the products, those substances that have
been created during the reaction process. Energy may be on either side of
the equation.
Another way to display it is:
REACTANTS
PRODUCTS
The reaction may be “exothermic” (giving off energy in the form of heat), or
“endothermic” (taking in energy, in the form of heat, to make the reaction
work).
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The chemical equations must be balanced. The number of atoms of each
element on the left equals the number of atoms of the same element on the
right. Matter cannot disappear.
Example
An example would be the reaction of gasoline with oxygen:
C8H18 + O2 = CO2 + H2O
This equation is not balanced. Why? Well, on the left side there are 8
atoms of carbon. On the right side, there is only one atom of carbon. Also,
there are 18 atoms of hydrogen on the left, but only 2 on the right. There
are 2 atoms of oxygen on the left, and 3 on the right. Since 18 does not
equal 2, and 3 does not equal 2, we must “manipulate” the formula so we
have the same numbers of both on each side. HINT: manipulate any “free
agents” available at the end of your chemical balancing. See that the
oxygen molecule, O2, is not combined with anything else on the left side, so
you would do that one last.
First, we see that 8 carbons are on the left, but only one is on the right, so
let’s multiply the CO2 molecule by 8, and this will then result in:
C8H18 + O2 = 8 CO2 + H2O
Is it balanced now? No. While there are 8 carbons on the left, and 8
carbons on the right, there are still 18 hydrogens on the left, and only 2 on
the right. So, let’s multiply water, H2O, by 9, which will result in:
C8H18 + O2 = 8 CO2 + 9 H2O
This gives us 8 carbons on both sides, and 18 hydrogens on both sides.
But is it balanced? Not yet. Why? There are still 2 oxygens on the left side
of the equation and 25 on the right side. So, to balance the equation, we
need to multiply the oxygen molecule on the left, O2, by 12 ½:
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C8H18 + (12 ½) O2 = 8 CO2 + 9 H2O
Now, is it balanced? Yes, but we usually don’t have fractional molecules or
fractional atoms. So, instead of having the number 12 ½, we choose to
multiply the entire chemical equation by 2:
2 C8H18 + 25 O2 = 16 CO2 + 18 H2O
Now, is everything done? Almost. We need to add the energy output of the
burning of gasoline:
2 C8H18 + 25 O2 = 16 CO2 + 18 H2O + Energy
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Physical Science Lab
I Title: Testing Chemical Change
II Purpose: To see the way a test kit changes with acids, bases, and neutral
fluids.
III Equipment
• A swimming pool test kit
• Acid (vinegar, or lemon juice)
• Base (colorless ammonia)
• Water
IV Procedure
1. Test each of the fluids listed above and observe, record each color.
V Data and Calculations
VI Results
VII Error
VIII Questions
1. Why do swimming pool service persons use test kits?
2. What would happen if your swimming pool had too much acid? Too
much base?
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Key Terms and Concepts
Electrolysis
balanced equation
endothermic
chemical change
nuclear change
exothermic
physical change
nuclear change
product
Reactant
Problems
1. Balance the equation
CH4 + O2 = CO2 + H2O
a) 2CH4 + O2 = 2CO2 + H2O
b) 2CH4 + O2 = 2CO2 + H2O + energy
c) CH4 + 2O2 = CO2 + 2H2O
d) CH4+ 2O2 = CO2 + 2H2O + energy
2. Complete, and balance, the equation
C3H8 + O2 =
a) C3H8 + 3 O2 = 3 CO2 + H2O
b) C3H8 + 3O2 = 3CO2 + H2O + energy
c) C3H8 + 5 O2 = 3 CO2 + 4 H2O
d) C3H8 + 5O2= 3CO2 + 4H2O+energy
3. In the burning of pure gasoline, what is NOT produced?
a) Heat
b) CO2
c) Smog
d) H2O
4. Are atoms of one element changed to atoms of any other element during
a chemical reaction?
a) Always
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b) Never
c) Sometimes
d) Rarely
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5. What is the balanced chemical equation for electrolysis?
a) 2 H2O + energy = 2 H2 + O2
b) 2 H2O = 2 H2 + O2
c) CH4+ 2O2 = CO2 + 2H2O + energy
d) 2 H2O = 2 H2 + O2 + energy
6. What is the balanced chemical equation for burning gasoline?
a)
C8H18 +
O2
=
CO2 +
H2O
b) 2 C8H18 + 25 O2 = 16 CO2 + 18 H2O
c)
C8H18 + O2
=
CO2 +
H2O + Energy
d) 2 C8H18 + 25 O2 = 16 CO2 + 18 H2O + Energy
7. What is the balanced nuclear equation for fusing hydrogen into helium?
a)
1
1H
= 2He4 + β+
1
C) 1H
= 2He4 + 2β+ + Energy
b)
1
1H
= 2He4 + β+ + Energy
d) 4 1H1 = 2He4 + 2β+ + Energy
8. Which of the following is NOT one of the states of water?
a) Ice
b) Liquid
c) Salt water
d) Water vapor
9. What does an endothermic reaction do?
a) takes in heat b) gives off heat c) produces water d) doubles energy
10. Which of these form products?
a) materials
b) heating
c) growth
d) reactants
Answers
1. d
3. c
5. a
7. d
9. a
2. d
4. b
6. d
8. c
10. d
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LESSON 8 THINGS TO REMEMBER
™ Water is never ionic
™ In the burning of gasoline, the products are carbon dioxide, water and
energy
™ When gasoline burns no atoms are changed into other atoms
™ In chemical change, the products are not the same substance as they
were before the reaction
™ Getting sawdust from lumber is a physical change
™ The burning of gasoline is exothermic
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LESSON 9 - OTHER PHYSICAL SCIENCES
Astronomy is among the oldest of the sciences. In reality, it is the branch
of physics known as “astrophysics.” Astronomy has two branches: stellar
astronomy (stars, galaxies, nebulae), and planetary astronomy (moons,
planets, comets, asteroids).
Planetary Astronomy
Studying the planets and the Moon
can be most interesting. Most of the
mass of the Solar System is the Sun
itself. But the Sun is a star, and will
be discussed later. The topics of
study in planetary astronomy include
planets, moon, comets, meteors, and
asteroids, and other things related to
them.
There are nine major planets. In their order from the Sun; they are
Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune, and Pluto.
To help you remember that, make up a “mnemonic” (word clue) to assist
you. For example, take the first letter of each of the planets and string them
together, like this:
MVEMJSUNP
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Of course, in and of themselves that won’t help much. But now use those
letters to make new words and thus, a sentence; the sillier, the better. How
about:
Main Valves Explode Making Janitors Stand Under New Pipes
You get the idea. There are many such “games” to help you remember.
There are two types of planets: big and small. The big ones are really just
large balls of gas, and they are given the name “Jovian Planets” – for Jove,
another name for Jupiter. The Jovian planets are Jupiter, Saturn, Uranus,
and Neptune.
The little planets are small balls of rock. They are Mercury, Venus, Earth,
and Mars. The planet Pluto may be included in here.
The four inner planets are called the Terrestrial Planets, since they are like
Terra, another name for Earth. Of course, Earth is an ideal place to live.
Venus is too close to the Sun, and therefore, too hot. Mars is too far away
and therefore too cold. Earth is “just right.” Mercury is even closer to the
Sun than Venus is. The Jovian worlds are in the frosty cold of outer space.
Seven of the nine major planets have moons. Mercury and Venus do not
have any moons. Earth has a moon called, “Moon.” Mars has two tiny
moons. Jupiter, Saturn, Uranus, and Neptune all have large numbers of
moons. In fact, those planets are almost like tiny solar systems. Pluto has
one moon that is almost as big as Pluto itself.
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Scattered throughout the solar system are the “leftovers”: the cosmic
invaders of comets, meteors, and asteroids. Comets are mostly dirty
snowballs with very long orbits. Asteroids are "wannabe planets” that never
got large enough, and meteors are just made of space dust.
Comets are usually in our skies every night. They may not be bright
enough to be seen easily. Meteors fall from the sky as the Earth gets near
them. Some people call them “shooting stars.” Asteroids are in various
locations, including a large number of them between Mars and Jupiter.
Our Moon is a lovely sight, of course. It travels around Earth in about a
month and goes through various shapes, or phases. Sometimes the Moon
covers the Sun, and that’s called a Solar Eclipse. Other times the Moon
“hides” behind Earth and grows dark in Earth’s shadow. That’s a Lunar
Eclipse.
Planets, moons, comets, meteors and asteroids form as part of a star’s
formation. They are made out of some of the original material that was
there for the star. However, only 20%
of all stars have “solar systems.”
Stellar Astronomy
Stars are so far away that they look
like small pinpoints of light. They are
not just tiny dots, however. They are
about the size of the Sun, which is our
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star. Our Sun is more than 300,000 times heavier than Earth, and
extremely hot. The “surface” of the Sun is 6,000 Kelvin (about 12,000
degrees Fahrenheit). However, the center of the Sun, and any star, is
millions of degrees, which is hot on any scale.
Stars, just like the Sun, create their energy by nuclear reactions. At the
center of all stars, the gas hydrogen is turned into helium, releasing a
tremendous amount of heat.
Stars begin as an enormously large “blob” of gas and dust. Gravity pulls it
all together, and eventually, it “ignites” into a nuclear-burning, selfsustaining star. And sometimes the star has planets. More often than not,
two or more stars will form out of the same blob of gas and dust. In fact,
about 60% of the stars are really “multiple” star systems.
Stars are so far away that we don’t tend to measure their distances in miles
or kilometers, but instead, in “light years.” As you have learned, light
travels about 300,000 km/s. Since there are about 31.7 million seconds in
one year, during a year’s time, light travels 9.5 trillion kilometers (5.9 trillion
miles). This distance is called a “light year”.
Stars take about 1 billion years to form. Then they last a long, long time.
Some live 10 billion years or more. Our Sun is 5 billion years old. When
stars get older, they first expand their outer layers and become quite large,
and much cooler. They are then called “Red Giants,” and they are so large,
their outer layers would reach out to Jupiter – or beyond! About 1 million
years after this, the outer layers escape into space, leaving a very small,
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dense, bright star called a “White Dwarf.” The size of a White Dwarf can be
about the same as Earth, but 300,000 times heavier! A few stars shrink
even smaller and become “Black Holes” and disappear.
Some stars form in groups called clusters. These can be relatively small
groups of 100 or fewer, or as many as a few million. However, once a
group of more than a billion stars forms, it is called a galaxy.
Our galaxy is called “the Milky
Way” because the word
“galaxy” comes from the
Greek word galactos, which
means “milky way.” Our
galaxy contains about 400
billion stars, and it also has
two smaller “satellite” galaxies
that go around it, just like a
moon orbits a planet.
In our “galaxy neighborhood” there are at least 20 galaxies. The largest in
the group is called the Andromeda Galaxy. It has slightly more than our
400 billion stars, and it is at a distance of 2 million light years away.
Andromeda also has two satellite galaxies revolving around it.
Galaxies come in different shapes and sizes, too, and they are at different
distances. The “closest” galaxies are less than 2 million light years away,
while the most distant are about 20 billion light years away.
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The most distant objects that we see are believed to be the nuclei of newly
forming galaxies. We call them Quasi-Stellar Radio Sources, or “Quasars”
for short.
Our universe, called “the Universe,” seems to be expanding, or getting
larger. If it were the shape of a ball, its diameter might be 40 billion light
years, or more. There are some mysteries left to solve, such as what
happens to a star once it shrinks down to the size of a pinhead, and then
disappears from time and space? This is the “black hole,” and it occurs
when very heavy stars collapse under the force of gravity until they vanish.
Do they go into another universe, or what? It is thrilling to think about.
Geology is the science of Earth. The word
geo is an ancient word for Earth, and logos
means “the study of.” Thus, geology is the
study of Earth. The science of geology is
really a branch of physics called “geophysics.”
More specifically, geology is the study of what
makes up the solid Earth, essentially from the surface to the core. As a
result, mountains, valleys, hills, craters, volcanoes, glaciers, lava, rocks,
and minerals are all part of geology. Geography is a branch of geology,
specifically dealing with the Earth’s surface. Cartography, which is part of
geography, is the study of map-making.
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Example
For great adventurers and explorers, a good map is a must. The famous
discoverer, Christopher Columbus, was not
only a sailor, but also a mapmaker.
The Earth’s Surface
On Earth, the GeoChemical Rock Cycle
is a cycle that rocks pass through. In this
cycle, volcanoes belch out hot, melted
material (called magma) from deep in the
Earth. As soon as this magma hits the air, it becomes lava. Some of the
lava cools and becomes hard. This is now called an “igneous” rock. Some
of this igneous rock gets washed away, and joins with other rocks. This is
called a “sedimentary” rock, such as limestone. Other rocks combine, and
under pressure, form a dense, heavy rock known as a metamorphic rock,
such as some granites. Then, over a long period of time, a few
metamorphic rocks get heated under pressure, melt, and re-join the hot,
molten material (magma) beneath Earth’s surface again. Thus goes the
cycle.
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Source: http://yates.nn.k12.va.us/images/rocks.gif, 01/19/2006.
The Inside of the Earth
Earth has several spherical
layers, or levels, beneath
the surface. The top 50
Inner Core solid
kilometers (30 miles) or so is
a very thin layer called the
Outer Core liquid
Lower Mantle Soft
solid
Upper Mantle
Plastic
Crust
Solid
“crust.” Below that is the
“mantle.” The upper mantle
and the crust is where all
earthquakes come from. The
lower mantle is very warm
and quite soft.
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Example
The study of Earthquakes is called “seismology.” The Earth’s crust is
divided into sections called “plates.” These plates “float” on the layer below
them – the mantle. These plates are not locked down, and they do move
relative to each other. When the plates move quickly, an earthquake
occurs. Sometimes earthquakes occur between two landmasses, such as
those in California over the past 30 years. Some occur between two parts
of the crust that are on the ocean floor.
The one on December 26, 2004 generated huge waves of water called
“tsunamis”. They caused great death and destruction along coastal areas
in such places as Thailand, Indonesia, Sri Lanka, and nearby areas.
Tsunamis are also sometimes called “tidal waves,” although they have
nothing to do with tides.
The three most active earthquake areas in the world include Turkey, Chile,
and Southern California. However, earthquakes can occur almost
anywhere.
Below the mantle is the outer core, which is liquid nickel-iron. Finally, at the
very core, no matter that it’s 3000 Kelvin or more, the pressure is so high
that it is solid nickel-iron.
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Example
In the Jules Verne book, Journey to the Center of the
Earth, a group of explorers is able to “climb down” to the
Earth’s very center. While there, they find a large ocean
of water. That scenario, however, is just fantasy. In
reality, we have a large core of rock-solid nickel-iron. The rotation of the
outer liquid core helps create the Earth’s magnetic field. A magnetic
compass can help you find the directions of north, south, east, and west.
The Earth’s insides are similar to those of other planets, too. For more
information on this, take a course in Earth & Space Science.
Meteorology sounds like the study
of meteors or rocks that fall from
outer space. That is not true. The
word Greek word meteor means
“high in the sky”. Those who study
the weather and the climate are
really studying what is going on in
the sky overhead – the air that is
“high in the sky.” A person who studies the weather is a meteorologist. The
science of meteorology is really the branch of physics called “atmospheric
physics.”
Example
Well, then, what do we call a person who studies those rocky meteorites
from outer space? A meteoriticist!
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In studying the Earth’s air, also
known as the Earth’s atmosphere,
scientists realize that the air is
thickest, or heaviest, at the bottom.
The air that is way up in the sky is
thin, such as the air at the top of a
mountain. Anyone who lives near
the ocean, but vacations in the mountains, immediately notices a lack of
oxygen when they go up high, causing them to gasp for breath.
The Earth’s atmosphere has six lower levels. The lowest level of Earth’s
atmosphere, which is about 8 to 11 kilometers up (5 to 7 miles) is called the
“troposphere.” The
Latin word tropo
means “to change” or
“to turn,” and, it has
the same root as the
word “tropic.”
The word “sphere”
means a ball. The
troposphere is where
we live. The air is most
turbulent here.
Above the troposphere is the mesosphere (meso means “middle”), and the
two are separated by a boundary called the “tropopause” (“pause” means
“to stop.”) The lowest level of the mesosphere is often called the
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“stratosphere”. That is where the “jet stream” is located and where
commercial airline jets fly. The word “stratos” comes from the Latin stratus,
meaning, “to spread out.”
Above the mesosphere is the ionosphere (from “ion,” a charged particle),
where the air is extremely thin. However, the few atoms that are in the
ionosphere get turned into ions (they lose electrons) when the strong solar
rays hit them. The boundary between the mesosphere and ionosphere is
called the “mesopause.”
Finally, the most outer part of Earth’s air is the exosphere (exo means
“away” or “out from,”) meaning the most far away sphere of air. It is virtually
a perfect vacuum out there.
Weather changes occur due to the Sun’s heat combined with the Earth’s
rotation. Local conditions, such as mountains and nearness to water, also
affect weather.
Clouds
Clouds are an important part of
weather. Most people think clouds
are made of water vapor.
However, water vapor is invisible.
Clouds are made up tiny water
droplets, and they are constantly
changing. You will never see the
same cloud twice, even if you look away for one second.
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You may see different types of clouds twice, but not the exact same cloud.
And different types of clouds exist at different levels.
The Main Types of Clouds Are:
1. High – Cirrus family (Cirrus, Cirrostratus, Cirrocumulus)
2. Middle – Alto family (Altostratus, Altocumulus)
3. Low – Stratus family (Stratus, Stratocumulus, Nimbostratus)
4. Vertical – Cumulus family (Cumulus, Cumulonimbus)
Nimbus is Latin for “cloud.” The vertical clouds often lead to heavy summer
thunderstorms. And sometimes there are very heavy desert
thunderstorms, but the raindrops evaporate before they ever reach the
ground!
Climate
Climate (from the Greek klima, meaning the angle of the Sun) is the
average type of weather in a certain location, over a period of many years.
The climate in any one place is the same for many centuries.
Examples
Meteorologists classify climatic regions in a number of ways. However, for
this lesson, we shall use only two: by temperature and by precipitation.
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There are five climate zones based upon temperature:
1. Tropical (averages above 20° C or 68° F all year). Examples are the
tropics, such as the Caribbean.
2. Subtropical (averages above 20° C at least 4 months and the rest no
colder than 10° C). Examples include states like Georgia and
Alabama.
3. Temperate (4 - 12 months at 10° - 20° C). States like Missouri and
Illinois.
4. Cold (at least 1 month at 10° - 20° C, and the rest cooler). Canada is
an Example.
5. Polar (averages are below 10° C all year). Central Alaska.
There are eight climate zones based upon precipitation (rain or snow):
1. Equatorial (rain all year). Examples would include the Amazon.
2. Tropical (rainy summers and dry winters). South Florida.
3. Semi-agrid Tropical (dry most of the year, with some summer rain).
Parts of Texas and New Mexico.
4. Arid (dry all year). Las Vegas
5. Dry Mediterranean (dry most of the year, but some winter rain). Los
Angeles
6. Mediterranean (dry summers and rainy winters). Nice, Rome, Athens
7. Temperate (rain all year – but not as much as Equatorial). Missouri.
8. Polar (little rain or snow all year). Pt. Barrow, Alaska; Novosibirsk,
Russia.
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The one city in the United States with the “best” all-around weather is San
Diego, California. It is about 75 oF every day and about 55 oF every night all
year round, with many sunny days and not much rain. Yuma, Arizona, is
the “sunniest” city, with 360 days of sunshine per year. The Southeast is
very warm and very humid in the summer. The Southwest is very hot and
very dry in the summer. The Northern Plains and Northern New England
are bitterly cold in the winter. And there are many other examples. Consult
your local newspaper or news & weather station for daily and yearly
temperatures and precipitation.
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Physical Science Lab
I Title: Weather
II Purpose
To study wind, sky, rain, clouds, and other weather-related items.
III Equipment
• Access to a weather reporting source (newspaper, TV, radio, Internet)
• Calendar
• Thermometer
• Barometer (optional) measures atmospheric pressure
• Anemometer (optional) measures wind speed
IV Procedure
1. Check local listings of the highs and lows for the past 5 days. Record
2. Check local listings of the weather conditions for the past 5 days
(cloudy, windy, rainy, sunny, etc.)
3. Observe the weather over the next 5 days (highs, lows, conditions) and
record.
4. Make a prediction of the weather over the next 5 days (without cheating
and looking in the paper). Record.
5. After that 5 days, check the local listings of what the weather really was,
and compare what really happened with what you had predicted.
V Data and Calculations
(The data will be your table of temperatures, etc., vs. dates)
VI Results
Well?
VII Error
If you were not exactly correct, why not?
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VIII Questions
1. Why do they call meteorology an inexact science? Isn’t science exact?
2. How many climate zones are in the United States?
3. Which city has the most moderate, or, even temperature, in the U.S.?
Key Terms and Concepts
Planet
climatic regions
climate
Moon
precipitation
meteorology
Comet
meteoritics
Earth’s Magnetic Field
Asteroid
Inner and Outer Core Seismology
Meteor
Tsunami
Mantle
Sun
Earthquakes
GeoChemical Rock Cycle
Solar System
Crust
Geograp
Star
Cartography
Quasar
Red Giant
“Geology”
Cluster of Stars
White Dwarf
Galaxy
Black Hole
Igneous, Sedimentary, Metamorphic
troposphere, mesosphere, ionosphere, exosphere and all other
atmospheric levels
clouds and their various types
Problems
1. What is the difference between a planet and a star?
a) Planets orbit stars
b) Stars orbit planet.
c) Planets move, stars do not
d) Planets have names, starts do not
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2. What is the difference between a planet and a moon?
a) Moons move, planets do not
c) Moons orbit planets
b) Planets have names, moons do not
d) Planets orbit moons
3. For each term in Column A, choose the correct definition from Column
B.
Column A
Column B
i)
Comets
a) Shooting stars
ii)
Meteors
b) Wannabe planets
iii)
Asteroids
c) Moons
d) Dirty snowballs
4. How many planets are in the Solar System? Which is NOT one of them?
a) 9, Titan
b) 8, Venus
c) 9, Jupiter
d) 8, Mars
c) Andromeda
d) Constellation
c) 400 million
d) 400 billion
5. What is the name of our galaxy?
a) Nestle
b) Milky Way
6. How many stars are in our galaxy?
a) 9
b) 1,000
7. What is formed when a star shrinks until it vanishes?
a) Meteor
b) Black hole
c) Dwarf
d) Super nova
8. What is the name of the galaxy-like nucleus at the edge of the universe?
a) Asteroid
b) Constellation c) QUASAR
d) Andromeda
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9. “Geology” is the study of:
a) Earth
b) Gems
c) Weather
d) Stars
10. ____________ was a mapmaker and famous discoverer.
a) Ben Franklin b) Columbus
c) Galileo
d) Eric the Red
11. What is a tsunami?
a) A Sushi dish
c) A Chinese train station
b) A Japanese car
d) A large wall of water
12. What region of the Earth does NOT have great earthquake activity?
a) Chile
b) Canada
c) S. California
d) Turkey
13. What causes the Earth’s magnetic field?
a) Wind from the Sun
c) Rotation of outer liquid core.
b) Light from the moon.
d) Rotation of the oceans.
14. What is the job title of a person who studies meteorology?
a) Meteorist
c) Weather man
b) Meteorology person
d) Meteorologist
15. What is the job title of a person who studies meteorites?
a) Geologist
b) Meteoriticist
16. Explain the GeoChemical Rock Cycle
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c) Star chaser
d) Scientist
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17. Describe the layers of the Earth’s insides
18. Name the six lowest levels of Earth’s atmosphere
19. Name the 4 main cloud types.
20. Climate can be classified as a function of what two items? List the
subcategories of climate regions for each of these two.
Answers
1.
a
5. b
11. d
2.
c
6. d
12. b
3.
i
d
7. b
13. c
ii
a
8. c
14. d
iii b
9. a
15. b
4.
a
10. b
16. The GeoChemical Rock Cycle is: magma to lava to igneous to
sedimentary to metamorphic to magma.
17. The layers of the Earth’s interior are, from top to bottom: crust, upper
mantle, lower mantle, outer core, inner core.
18. The six lowest levels of Earth’s atmosphere are: troposphere,
tropopause, stratosphere, mesosphere, mesopause, and ionosphere.
19. The 4 main cloud types are high, middle, low, and vertical.
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20. Climate can be classified as a function of temperature or precipitation.
The subcategories regarding temperature and precipitation are as
follows:
temperature
precipitation
Tropical
Tropical
Subtropical
Semiarid Tropical
Temperate
Arid
Cold
Dry Mediterranean
Polar
Mediterranean
Temperate
Polar
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LESSON 9 THINGS TO REMEMBER
™ Vulcan is not a major planet in our Solar System
™ The name of our galaxy is the Milky Way
™ A tsunami is an earthquake-generated tidal wave
™ There is a high rate of earthquake activity in Chile
™ Exosphere is not one of the lowest levels of Earth’s atmosphere
™ Climate is a function of temperature and precipitation
™ A comet is a snowball in space
™ An asteroid is a minor planet
™ The rotation of the Earth’s outer liquid core causes the Earth’s
magnetic field
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END OF COURSE REVIEW
™
There are 24 time zones around the globe
™
There are 3600 seconds in an hour
™
Time is one-dimensional and space is 3-D
™
A photographic image is two-dimensional
™
A natural biorhythm is the human heart (at rest) beating about once
per second
™
Two liters of soda filling a plastic bottle measures that soda’s volume
™
There are 1,000 grams in a kilogram
™
Assume that the equator of the Earth is 24,200 miles in
circumference. Now, pretend that you are standing somewhere on
the equator, such as in the country of Ecuador. Now, if the Earth
turns once, completely, in 24 hours, then you be going, in miles per
hour, 1,000 even if you were standing still
™
Your weight on Earth is greater than your weight on the moon. And
your weight on the moon would be less than your weight on Earth
™
One pound of solid water is less dense then one pound of liquid water
™
The momentum (in kg-m/sec) of a 910=kg car traveling north at 133
meters per second is 12,100 (910 kg X 133 m = 12,100 kg-m/sec)
™
The kinetic energy of a 25-gram bullet traveling at 500 m/s is 3125 KJ
™
Newton’s Laws of Motion do not include objects in motion coming to
rest
™
Every second that any solid object falls toward Earth, its speed
increases by another 9.8 m/s. After10 seconds of “free fall” all objects
falling are traveling at the same rate of speed
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™
Styrofoam has a higher heat capacity than copper, aluminum, plastic,
or paper
™
To convert Fahrenheit to Celsius (Centigrade), subtract 32 and divide
by 1.8 (Dividing by 1.8 is the same as multiplying by 5/9)
™
To convert Celsius (Centigrade) to Fahrenheit, multiply by 1.8 and
add 32 (Multiplying by 1.8 is the same as multiplying by 9/5)
™
The Sun heats the Earth by radiation
™
The speed of a wave “s” is the wave length times the frequency
™
Radio waves travel through empty space at 300,000 Km/s
™
A proton is 1,800 times heavier than an electron
™
Teal is not a color of the rainbow
™
Gamma rays are the most energetic electromagnetic radiation
™
There are 6 colors outside the rainbow
™
50 Coulombs of electrons flowing past the middle of a copper wire in
10 seconds, then the electric current in that wire is 50 amps
™
A wave of electromagnetic radiation has more energy if it has higher
frequency
™
There is 1 electron in a neutral hydrogen atom
™
There are 0 neutrons in almost all neutral hydrogen atoms
™
Positrons are positive electrons
™
4 atoms of hydrogen are needed to create one atom of helium
™
Heavier and more complex elements are made one at a time from the
fusion of atoms of hydrogen, helium, and heavier elements
™
Einstein’s formula says that Energy is equal to the mass of the matter
that is lost times the speed of light squared
™
Ne does not represent one molecule of a substance
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™
Producing electric power with a nuclear reactor produces several
nuclear fission reactions
™
An isotope is a version of an element
™
Starting with 1,000 grams of radium, there would be 125 grams left
after 3 half lives
™
Removing salt from seawater is called desalination
™
Concrete is said to be heterogeneous
™
Before becoming a diamond, coal must become the following first:
rotting plants, peat, coal and then diamond
™
In a solution, the solute particles are the smallest
™
Water is never ionic
™
In the burning of gasoline, the products are carbon dioxide, water and
energy
™
When gasoline burns 0 atoms are changed into other atoms
™
In chemical change, the products are not the same substance as they
were before the reaction
™
Vulcan is not a major planet in our Solar System
™
A tsunami is an earthquake-generated tidal wave
™
There is a high rate of earthquake activity in Chile
™
Exosphere is not one of the lowest levels of Earth’s atmosphere
™
Climate is a function of temperature and precipitation
™
The rotation of the Earth’s outer liquid core causes the Earth’s
magnetic field
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