3. Chapter One: What Physics and
Chemistry are About
• 1.1 The Physical Science in Your Life
• 1.2 Describing the Physical World
• 1.3 Energy, Matter, and Change
5. 1.2 Describing the Physical World
• Energy is how the
universe changes.
• A fast ball has
more energy than
a slow ball.
6. 1.2 Describing the Physical World
• Up-down, right-left,
and forward-
backward are three
directions of space.
• To completely
understand the
motion of a ball we
need to know its
exact path.
7. 1.2 Describing the Physical World
• Time is our reference for understanding change.
• As time goes on, each change causes other
changes, which cause still more changes.
8. 1.2 Mass
• Mass is measured in kilograms (kg).
One gram (g) is one-thousandth of a kilogram.
How many grams is each item above?
9.
10. 1.2 Mass
• For small amounts of
mass, the kilogram is too
large a unit to be
convenient.
• In the laboratory you will
usually measure mass
with a balance.
• The balance displays
mass in grams.
11. 1.2 Length and Distance
• Distance is the amount of space between
two points.
• Distance is measured in units of length.
12. 1.2 Length and Distance
• Some of the commonly used units of
length include inches, feet, miles,
centimeters, kilometers, and meters.
13. 1.2 Length and Distance
• The names of units in
the metric system are
based on multiplying
by ten.
• Almost all fields of
science use metric
units because they are
easier to work with.
14.
15. 1.2 Measuring Length
• For ordinary lengths you
must measure in the
laboratory a meter stick is
the most convenient tool to
use.
• For very small lengths, such
as the size of a bacteria,
scientists use measuring
instruments that fit into a
microscope.
16.
17. 1.2 Time
• Time has two
important meanings.
–What time is it?
–How much time?
18. 1.2 Time
• Units for time include:
– seconds
– minutes
– hours
• The second is the basic unit of time in
both the English and metric systems.
19. 1.2 Mixed units of time
• Time is often expressed
in mixed units.
• This timer shows the
time for a race as 2
hours, 30 minutes and
45 seconds.
20. 1.2 Mixed units of time
• A microwave oven
can program time in
either mixed units
(minutes and
seconds) or in a
single unit (seconds).
Explain how 1:30 and
0:90 will result in the
same cooking time.
