PHYSICAL SCIENCE CHAPTER 1 NOTES
The Nature of Science
SECTION 1 (THE METHODS OF SCIENCE)
1) Science is a process that based on inquiry that helps develop explanations about events in nature. Three main categories of
science.
a) Life science—is the study of living things.
b) Earth Space Science—study of earth and space.
c) Physical Science—study of matter and energy.
2) Scientific Method—is an organized set of investigation procedures. The steps used in the scientific process (method) are the
following. Note: they do not all have to be used nor do they have to be in order.
i) Stating a problem
ii) Researching and gathering information
iii) Forming a hypothesis
(1) Hypothesis—is a possible explanation for a problem using what you know and what you observe.
iv) Testing a hypothesis by performing experiments. Experiment--tests the effect on one thing on another using a
control.
(1) Variable—is a quantity that can have more than a single value.
(a) Dependent variable— the value of this variable is dependent upon changes in a different variable.
(b) Independent Variable—is the variable that gets changed and influences the value of the dependent
variable.
(c) Constant—is a variable that does not change. For example, for all practical purposes, acceleration due to
gravity is 9.8 m/s2.
(d) Control—is the standard by which the test results can be compared.
v) Data analysis—typically need sophisticated software to handle the data loads that today’s experiments develop.
vi) Drawing conclusions (either supporting or not supporting the hypothesis). Conclusion--is a judgment based on the
analysis of data gathered from lab experiments or field studies.
3) Communication (ie. a paper only after peer review) Scientists will not be biased in the conclusion of an experiment. Only
findings that have gone through the rigors of a scientific panel are ready to be published.
4) Model—represents an idea, event, or object to help people better understand it. Can be a computer simulation.
5) Theory—is an explanation of things or events based on knowledge gained from many observations and investigations.
6) Law--is a summary of many experimental results and observations, it describes what happens, not why it happens. Usually
presented by mathematical equations such as
m
D
or F  m a
V
SECTION 2 (STANDARDS OF MEASUREMENT)
1) A Standard—is and exact quantity that people have agreed to use for a comparison.
2) Standard Units--(SI)--is the international system of units. When taking any measurement it MUST INCLUDE BOTH A
NUMBER AND A UNIT OF MEASUREMENT. All SI standards are universally accepted and understood by scientists.
a) Length--SI unit is the meter (m)
b) Mass--SI unit is the kilogram (kg)
c) Volume--SI unit is the liter (L)
d) Temperature--SI unit is the Kelvin (K) Note we will use Celsius (C)
e) Time--SI unit is the second (s)
f) Electric Current—SI unit is the Ampere (A)
3) Volume--is the amount of space occupied by an object.
a) The volume of a solid is measured in meters3. The volume of a liquid is measured in Liters.
4) Any equality can be written as two or more ratios. This will help us keep
track of the units. Keeping track of our dimensions will be a key issue for
us for the entire year. The following are examples of how to use equalities
to do dimensional analysis.
1ml  1cm3 can be used as
V  l  wh
1ml
1cm3
or
3
1cm
1ml
Example: Convert 20 ml to cm3 .
5) Weight is the mass of an object multiplied by the acceleration of gravity. W  m g
 1cm3 
3
  20cm
1
ml


 20ml  
PHYSICAL SCIENCE CHAPTER 1 NOTES
The Nature of Science
6) Matter—anything that takes up space and has mass.
7) Mass—is a measurement of the quantity of matter in an object.
3
8) Density--is the ratio of the mass of an object to its volume. Density and has the units of kg/m .
D 
m
V
SECTION 3 (COMMUNICATION WITH GRAPHS)
1) Much of the data that scientist gather is analyzed using graphs. Graph—is a visual display of information or data.
a) Line graph shows the relationship between the independent and dependent variables.
b) Bar graph is useful for comparing information collected by counting. Useful if data does not change continuously.
c) Pie graphs show how some fixed quantity is broken down into parts.
SECTION 4 (SCIENCE AND TECHNOLOGY)
Technology—is the application of scientific knowledge to benefit people.
Society—is a group of people that share similar values and beliefs.