Section Review Answers
Chapter 1
Section 1
1. Chemistry is the study of matter and its changes.
Physics is the study of forces and energy and their
interaction with matter.
2. Science is knowledge about the nature of
things that is obtained by doing experiments.
Technology is the application of science.
Improving technology involves finding a use for
a scientific discovery. However, some scientific
discoveries cannot be made until a certain technology exists.
3. A scientific law describes how things work based
on experimental observations. Examples may
vary, but could include the laws of gravitation
and the conservation of matter.
4. A law summarizes an observation; a theory
explains observations.
5. A scientific theory may change if new discoveries
are found that cannot be explained by the theory,
but are supported by experimental evidence. A
new theory that can explain both the new and the
old observations would take the place of the old
theory.
6. A model is used to study or make predictions
about an object or situation the model represents. One example of a model is a computer
model that is used to design bridges and
buildings.
7. He did not give up after his experiment did
not give the results he expected. Instead, he
asked more questions and performed more
experiments to learn what was causing the
glow.
8. A guess or opinion is usually an unsupported statement. A scientific theory uses
repeatedly tested results to explain observed
events.
9. Your answer may vary.
Section 2
1. A hypothesis is a possible answer to a question
that can be tested. An example would be, “I can
pass the test if I study at least 5 hours.”
2. No experiment should be called a failure since
an experiment that produces unexpected results
provides a chance to learn something new.
3. An SI base unit is a single unit while a derived
unit is a combination of base units. Base units
include: seconds, meters, kilograms, kelvins,
amperes, moles, and candelas. Examples of
derived units include meters squared (m2) and
milliliters (mL, cm3).
4. Answers may vary. Sample answers: mass: solid
food items, people, and mail; volume: liquid food
items, gasoline, shampoo; length: rope, distance,
height
5. The scientific method involves critical thinking
in that it entails thinking about a problem and
making objective judgments about results.
6. It is much easier to determine which factor your
experiment depends on if you only check one
factor at a time. If you change more than one
thing and something unexpected happens, you
will not know what caused the result.
7. There are still scientific theories that have not
been verified because the tools needed to test
these theories do not yet exist.
8. The correct answer is that both weigh the
same. A reason for an incorrect answer
might be that mass is confused with volume
or density, and a given volume of feathers
would be much lighter than the same volume of lead.
9. a. 50 kg _ (1,000 g/1 kg) = 50,000 g
b. 4,630 _g _ (1 g/1,000,000 _g) = 0.00463 g
10. 0.42 km _ (1,000 m/km) = 420 m
Section 3
1. Line graphs are best for continuous changes.
2. Pie charts show the parts of a whole. An example
is the percentages of the different types of music
that make up a CD collection.
3. Scientists use significant figures because they
indicate how precise their calculations really are.
4. The throws were precise because they all hit the
dartboard near the same spot. However, they
were not accurate because they were not close to
the bull’s eye.
5. a. 1.54 _ 104 mm3
b. 2.05 _ 103 mL
6. a. 9.20 _ 107 m2
b. 9.66 _ 10-5 cm2
7. a. 1.2 _ 103 cm3
b. 2.6 _ 102 m/s
End of chapter Review Answers
Using Key Terms
2. Physical science is no longer the
study of only the nonliving world.
As knowledge has increased,
scientists have learned that the
discoveries in one area are applicable to another. For example,
chemistry, a physical science,
applies to living beings. This field
of study is called biochemistry.
3. It has been observed repeatedly, and it does not attempt to
explain why the sun sets in the
west.
4. The rotation of Earth causing the
sun to set could be considered
a scientific theory because it is
a tested, possible explanation of
why the sun sets in the west.
5. Mass is a quantity of matter,
whereas weight is the force with
which Earth’s gravity pulls on
that quantity of matter.
6. Scientific notation would be
used to express 35 nanometers
in terms of meters because it is
0.000000035 m. Using scientific
notation decreases the number
of zeros that need to be written
and decreases the possibility of
errors in calculations.
7. The measured mass of the
elephant is accurate because it is
very close to the actual weight of
the elephant.
Understanding Key Ideas
8. d
9. b
10. a
11. d
12. c
13. a
14. c
15. b
16. b
17. b
Math Skills
27. a. 2.2 _ 104 mg
b. 3.7 _ 10-6kg
28. a. 2.6 _ 1014 A•s
b. 6.42 _ 10–7 m3/s
29. a. 7.4 m
b. 362.00 s
30. a. 133 m2
b. 210 L/min