Measurement
In this chapter we will explore the
following concepts:
1. Measurement of a physical parameter
2. Units, systems of units
3. Basic units in mechanics
4. Changing units
Stating a Measurement
In every measurement there is a
Number
followed by a
 Unit from measuring device
Standards of Measurement
When we measure, we use a measuring tool to
compare some dimension of an object to a
standard.
Basic & Derived Quantities
 Basic
Quantity  Must be defined in terms of a
standard (meter, kilogram, second).
 Derived
Quantity  Defined in terms of
combinations of basic quantities

Unit of speed = meter/second = m/s
International System of Units:
In this system the units for the base
quantities are:
Parameter
Length
Unit Name
Symbol
meter
m
Mass
kilogram
kg
Time
second
sec or s
Unit of Length: the Meter
A meter is a unit of
length, currently defined
as the distance light
travels
within
1/299782458th
of
a
second.
Time Unit –second (s)
The time needed for a cesium-133 atom to perform 9,192,631,770
complete oscillations
Volume Unit – the Liter (L)
Volume is the amount of space
occupied by a substance.
S.I unit of volume is liter (L).
The milliliter (ml) is commonly
used for measuring smaller
volumes of fluids.
1 gallon = 4 quarts
1 liter (L) = 1.06 quart
1 quart = 946 mL
1 L = 10 deciliters (dL)
= 100 centilliters (cL)
= 1000 milliliters (mL)
Mass
The mass of an object is a measure of the
quantity of material it contains.
In the SI system, the mass unit is the
kilogram (kg).
In the metric system, the mass unit is the
gram (g).
Compare to US weight units:
1 kg = 2.20 lbs
1 lb = 454 grams
Temperature Scales
 The degree of
hotness or coldness
is called temperature.
 The S.I unit of
temperature is kelvin
Other Scales:
1. Celsius (C) scale
2. Fahrenheit (F) scale
 1 C = 1.8 F
Other Systems of Units
CGS
centimeter-gram-second
FPS
foot-pound-second
Learning
Check
From the previous slide, state the tool (s)
you would use to measure
A. temperature ____________________
B. volume
____________________
____________________
C. time
____________________
D. weight
____________________
From the previous slide, state the tool (s) you would
use to measure
A. Temperature
B. Volume
C. Time
D. Weight
thermometer
measuring cup, graduated cylinder
watch, clocks
spring balance
Unit conversions
We will work exclusively in SI (MKS)
units!
Unit Conversion
Learning Check
What are some S.I units that are used to
measure each of the following?
A. length
B. volume
C. weight
D. temperature
Some possible answers are
A. length
inch, foot, yard, mile
B. volume cup, teaspoon, gallon, pint, quart
C. weight ounce, pound (lb), ton
D. temperature F
Units in the Metric System

length
meter
m

volume
liter
L

mass
gram
g

temperature
Celsius
°C
Learning Check
Identify the measurement in metric units.
A. John’s height is
1) 1.5 yards
2) 6 feet
3) 2 meters
B. The volume of Pepsi in a big bottle is
1) 1 liters
2) 1 quart
3) 2 pints
C. The mass of a lemon is
1) 12 ounces 2) 145 grams 3) 0.6 pounds
Solution
A. John’s height is
3) 2 meters
B. The volume of Pepsi in a big bottle is
1) 1 liter
C. The mass of a lemon is
2) 145 grams
Changing Units
Units of Volume:
• The SI unit of volume is the cubic meter (m)3.
• A more convenient unit of volume for everyday
use is the liter, a non-SI unit.
• A liter (L) is the volume of a cube that is 10
centimeters (10 cm) along each edge (10 cm 
10 cm  10 cm = 1000 cm3 = 1 L).
Units and Quantities
Units of Temperature
Scientists commonly use two
equivalent units of temperature,
the degree Celsius and the kelvin.
Units and Quantities
 The
joule (J) is the SI unit of energy.
 One calorie (cal) is the quantity of heat that raises the
temperature of 1 g of pure water by 1°C.
Section Quiz.
1. Which of the following is not a base SI unit?
 gram
 meter
 second
 mole
Section Quiz.
3.
A temperature of 30 degrees Celsius is equivalent to
 303
K.
 300 K.
 243 K.
 247 K.
THE END