How to teach Science?
Students should do science
•Observation and hypothesis
•Measurement
•Collecting, organizing and
interpreting data
The Learning Cycle
Learning theory tells us•Learning proceeds best by an interaction of learner
with environment
•If this interaction results in mental disequilibrium,
then when mind may reestablish equilibrium at a
higher mental level
•Peer interaction is important in this process since
peers think along similar ways.
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Learning Cycle
Exploration
•Open ended
•Social Interaction
Concept Invention or Formation
•Guided Activities leading to formation of concept
Application
•Use the concept learned
Our Base Ten Number System
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Exponents
Examine the following series:
10 = 10, or 101
100 = 10 x 10, or 102
1000 = 10 x 10 x 10, or 103
10,000 = 10 x 10 x 10 x 10, or 104
The superscript numbers 1, 2, 3, etc. are
called exponents. Notice that increasing
the exponent by one is the same as
multiplying by 10.
It may help to think of the exponent as the
number of zeroes following a 1.
106 = 1 followed by 6 zeroes, or 1,000,000
102 = 1 followed by 2 zeroes, or 100
100 = 1 followed by no zeroes, or 1
Negative Exponents
We can extend this idea even further. Each time the
exponent decreases by one, the number is divided by 10.
10-1 = 0.1 (or 1/10)
10-2 = 0.01 (or 1/100)
10-3 = 0.001 (or 1/1000)
Remember that 102 means 1 followed by 2 zeroes.
Conversely, 10-2 means 1 preceded by two zeroes.
Counting the one to the left of the decimal point, 0.01 has
two zeroes in front of it.
Any number can be represented as some integer times 10
raised to some exponent. For example:
30 can be represented as 3 x 101
30,000 can be represented as 3 x 104
0.003 can be represented as 3 x 10-3
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The Metric System
The system of measure used in the United States -- based
on inches, feet, miles, etc. -- is not convenient for scientific
use. The metric system is much simpler and is used for all
scientific measurements, from the distance between galaxies
to the size of an atom.
The metric system was expanded in 1960 into the International
System of Units (metric units are therefore sometimes called SI
units). The major features of both systems are:
• The use of decimals
• A system of prefixes
• Standards defined in terms of basic, unchanging
properties
physical
The Meter
1 Meter
1/10
1/100
1/100
1=100
.1=10-1
.01=10-2
.001=10-3
deci
centi
milli
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Metric Ruler
1000
100
10
1 Meter 1/10
10=101
103
102
kilo
hecto deka
1=100
1/100
1/100
.1=10-1 .01=10-2 .001=10-3
deci
centi
milli
How long is the block
L= ____ cm _____ m _____
dkm ______km
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Metric Prefixes
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Metric Prefixes
Large Prefixes
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If I tell you that object A is 0.00000003 inches in
diameter and object B is 0.0000001 inches It's easier
to measure objects using readable numbers such as
1, 3.7, or 120, rather than numbers with lots of zeroes
Measuring a Cell
When studying cells under a
microscope, we soon discover that
most cells are in the size range of
10-6 to 10-4 meters. Microbiologists
use the micrometer (µm, also called
the micron) as their standard unit of
length, and talk about a bacterium
being 1.5 µm long and a
lymphocyte 10 µm in diameter.
Since the diameter of the smallest
atom (hydrogen) is just 10-10 m, many
chemists use the nanometer (nm) to
record molecular and atomic sizes.
One hydrogen atom is 0.1 nm in
diameter.
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History of the metric system
The International Bureau of Weights and Measures (Bureau
international des poids et mesures, acronymed “BIPM”) in
Sèvres, France.
Metric Units
Mega kilo
106
hecto deka
1000 100
103 102
10
101
Meter deci centi milli micro
Gram
Liter
Byte
Hertz
1
.1
.01 .001
100 10-1 10-2 10-3 10-6
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Astro Distances
Some well known distances (meters)
Radius of Earth
Earth to Moon
Earth to Sun
Earth to nearest Star
6 x 106
8 x 108
2 x 1011
4 x 1016
Length of housefly
Dust particles
Cell
Atom
5 x 10-3 (5mm)
1 x 10-4 (0.1mm)
1 x 10-5
1 x 10-10
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Units in Science-Area
Area is Units squares
square cm (cm2), square feet (ft2), sq m (m2), sq miles (mile2)
Why is L x W not a definition of
Area?
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Units in Science- Volume
1 cm3
1 dm3=
1 ft3
1 liter
kiloL HectoL dekaL Liter deciL centi L milli L
The Graduated Cylinder
If a stone is dropped, water
level goes up
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Measuring Mass
79.3 grams
kilogram Hectogr dekagr Gram decigr centi gr milligram
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