# Physical Science

```Physical Science
Ch. 1 Part II
Physical Science Methods
How Familiar Are You with Units of
Measurement?

10 km is about how far in miles?

A person who has a mass of 75 kg
weighs about how much in pounds.

About how much is a quart, and
how many quarts are in a 2 liter
bottle?

10 km = 6.2 miles

75 kg = 165 pounds

2 liters = 2.12 quarts
• If a long-jumper goes 7.255
m, is that good or bad?
• The speed limit says 104
km/hr. How fast is that?
• The boy weighed 78 kg.
What weight class will he
wrestle?
Standards

A standard is an exact quantity used for
comparison.
There are 2 commonly used systems of
measurement. The SI system (worldwide)
and English units (primarily in the U.S.).

How many cubits from one side of the room
to the other?


Why do you think the U.S. does not
use the SI system as much as the
rest of the world?
What are some SI units which
we see commonly used in the
U.S.?
SI System of Measurement

The SI system is a base ten system of
measurement. All units are either multiples
of 10, or decimals.
Prefixes added to root words will tell you
what multiple a measurement is.
For example........
Centi- = 1/100 or .01
1 meter = 100 cm
Milli- = 1/1,000 or .001
1 meter = 1,000 mm
Kilo- = 1,000X
1,000 meters = 1 km
Time
• Time is the interval between two
events, and is the only
measurement which uses the
same units (seconds) for both SI
and English measurements.
Length
 Length is a measure of the distance
between 2 points.
 The SI unit for length is the meter (m).
• The lead in a mechanical
pencil is usually measured
in millimeters (mm),
referring to it’s width.
Mass

Mass is a measure of the amount of matter in an
object.
The SI unit for mass is the kilogram (kg).
Mass is measured using a balance (not a scale.).
• The formula for mass is
Mass = Density x Volume
We'll use this formula later on.
Also, 1 kg = 2.2 pounds
A wood dowel, metal rod, and a candle all
have different masses, even if they're the
same size.
Is mass the same as weight?
Explain.
Volume

Volume is the amount of space occupied
by an object (how big it is).

For a regularly shaped object (square or
rectangular) volume is measured in cm3.
The formula is length x width x height.
• What is the volume of the object shown
below?
• If you have an object that is not a perfect
square or rectangle, how do you think you
could find it's volume?
• The best way to find the volume of an
irregularly shaped object is through water
displacement.
Density

Density is the amount of
mass an object or material
has, based on it's volume.
For example, if I have 2
objects the exact same size,
the one with more matter in it
is denser.
Like a bowling ball and a
styrofoam ball.
• Some examples of objects or materials
where density is important:
-a snowball
-liquid mercury
-humans floating and/or sinking
-warm and cold air
 The
formula for density is mass divided by
volume.
If mass is measured in grams and volume
is measured in cm3, the mass/density
would result in the label being g/ cm3.
Water for example has a density of
1 g/ cm3.
Derived Units

Units which are a combination of other
units are called derived units.

Ex.: cm3 for volume, mi/hr for speed
Temperature
• Temperature is a measure of the
average kinetic energy of the
particles in a sample of matter.
As you heat an object up, the
particles move faster (higher
kinetic energy), and the
temperature increases.
• The SI unit for temperature is the Kelvin.
Although the celcius and fahrenheit scales
are more commonly used.
Absolute Zero
• As the temperature of a material decreases,
particle movement slows. If the temperature
decreases to a point where particle
movement stops completely, this is called
absolute zero. (0 Kelvin)
• Absolute zero is theoretical, in
that it has never been achieved.
Temperature Conversions
• F = (C x 1.8) + 32
• C = (F - 32) x .55
• K = C + 273
• Ex.: If the temperature at the lake is 95
degree Fahrenheit, what is it in degrees
Celsius.
(95 – 32) x .55 = 34.65 degrees Celsius
Practice Problems
1. Convert 14 degrees
Fahrenheit to Celsius and to
Kelvins.
2. A rock dropped into a beaker
of water causes the water
level to rise from 415 mL to
675 mL. What is the volume
of the rock?
3. If the rock in problem #2 has a
mass of 520 g, what is it’s
density?
1. Convert room temperature (72 F) to:
A. Celcius B. Kelvin 2. A brick has a height of 8 cm, width of 12 cm, and length
of 20 cm. What is it’s volume?
3. If the brick in problem #2 has a mass of 3840 g, what is
it’s density?
4. Will the brick float or sink in water? Explain why.
5. A beaker has 235 mL of water in it. When a flashlight
battery is dropped in, the water level rises to 485 mL.
What is the volume of the battery?
6. If the battery in problem #5 has a density 1.5 g/cm3,
what is the mass of the
battery?
1. Convert 450 cm to:
A) Km
B) mm
2. If the melting point of lead is 327 degrees
Celsius, what is it in:
A) degrees Fahrenheit
B) Kelvins
3. An unknown metal has a volume of 5 cm3 and a
mass of 13.5 g. Using the table on pg. 19,
identify this metal.
Graphing
A graph is a visual display of information
or data.
Graphs often show patterns or
relationships in the data, and may be used
to predict future results.
Types of Graphs

There are 3 main types of graphs:
1. Line graph - shows trends or patterns over
time, usually with larger numbers
2. Bar graph - compares smaller values which
are usually counted
3. Circle (pie) graph - shows 1 fixed quantity
broken down into parts (usually percentages)
Line Graphs
• Line graphs use an X axis (horizontal) and
a Y axis (vertical) to plot data points, which
are then connected with either a straight or
curving line.
• The data measured on the X axis is the
independent variable, and the Y axis
shows the dependent variable.
The graph below shows how long students had to
wait while registering for school this past month.
• What does the graph show you?
• Hypothesize as to why Monday and Friday had
the longest wait times.
Bar Graph
• A bar graph is very similar to a line graph, just
with smaller numbers.
• Also, a bar graph shows information, but may or
may not show any patterns or trends.
For example........
Circle Graphs
• Circle graphs are best at showing
percentages.
• Examples of information you may see on a
circle graph include......
Opinion Polls
Do you favor or oppose Initiative and Referendum?
Election results
2004 Presidential Election
1%
3%
3%
Bush
47%
Kerry