Measurement-A Common
Language
EQ: How do I define mass, weight
and density?
Mass
• The measure of the amount of matter
an object contains
• Matter: The material that all objects
and substances are made up of
• Anything that has mass and takes up space is
matter
EQ: How do I define mass, weight and density?
Units of Mass
• International System of
Units
–Abbreviated as SI after its
French name Systeme
International
• The basic unit of mass in the
SI system is the kilogram.
EQ: How do I define mass, weight and density?
Milligrams
• Used to measure smaller
objects such as a paper
clip
EQ: How do I define mass, weight
and density?
Conversions
1 kg
=
1,000 g
1g
=
1,000 mg
EQ: How do I define mass, weight and density?
Mass
Measuring Mass
How does a
triple-beam
balance work?
•
•
A triple-beam balance works by
comparing the mass of the object you are
measuring to a known mass
When you use a triple-beam balance, you:
1. Place the object on the pan
2. Shift the riders on the beams until they balance
the mass of the object
• Start with the large rider (increments of 100)
• Next, the medium sized rider (increments of 10)
• Lastly, the small rider (increments of 1)
EQ: How do I define mass, weight
and density?
Mass
The Difference Between Mass and Weight
Weight
• The measure of the force
of gravity acting on an
object
EQ: How do I define mass, weight and
density?
How would your weight differ if
you were to travel to the moon?
• If you were to travel to the moon
your weight would be less.
• Your weight would be lesser because
the force of gravity is less.
• Weight is a factor of the force of
gravity
EQ: How do I define mass, weight and
density?
Why would your mass stay
constant if you were to travel to
the moon?
• Your mass would stay the same if you
were to travel to the moon because
mass is the amount of matter that an
object contains
• Since you are still made up of the
same amount of “stuff”, your mass
EQ: How do I define mass, weight
would not change
and density?
Why use the mass of an object
instead of its weight?
• mass does not change when the force of
gravity does
EQ: How do I define mass, weight
and density?
Volume
• The amount of space an
object takes up
EQ: How do I define mass, weight and density?
• Liter (L) –used to
measure the volume of a
liquid.
• Milliliter (mL) - To
measure the volume of
smaller liquids
EQ: How do I define mass, weight and density?
The instrument used to measure
the volume of liquids is called
the…
• Graduated cylinder.
EQ: How do I define mass,
weight and density?
This instrument has markings
that are in increments of…
• 1 milliliter (mL)
EQ: How do I define mass,
weight and density?
Meniscus
• The curve in the top surface of water
in the graduated cylinder
EQ: How do I define mass, weight and
density?
What is the proper way to read
a meniscus?
• Read the
milliliter marking
at the bottom
of the curve
EQ: How do I define mass,
weight and density?
Volume of a solid object
• To measure a solid objects that are
regular shaped, a formula for volume
can be applied
• To measure a rectangular object such
as a shoebox, multiply the object’s
length, width, and height
EQ: How do I define
mass, weight and
density?
The SI unit known for measuring
solids with a larger volume is
known as the…
• Cubic meter (m³) - The SI unit used
to measure solids with a larger volume
EQ: How do I define mass, weight and density?
Common Conversions For Volume
1L
=
1,000 mL
1 L
=
1,000 cm³
1 mL
=
1 cm³
EQ: How do I define mass, weight and density?
The formula for calculating the
volume of a rectangular object is:
Volume = Length x Width x Height
EQ: How do I define mass, weight and density?
Why is the unit cm³ used when
calculating the volume of a
rectangular object?
• When multiplying the object’s length,
width and height, the cm units are
also multiplied
cm x cm x cm = cm³
EQ: How do I define mass, weight and density?
Suppose a cereal box is 10 centimeters
long, 4 centimeters wide, and 20
centimeters high. What would be the
volume of the box?
Volume = Length x Width x Height
Volume = 10 cm x 4 cm x 20 cm
Volume = 800 cm³
EQ: How do I define mass, weight and density?
Volume of an Irregular Solid
• Water displacement method
• To measure the volume of an irregular
solid, immerse the object in water,
and measure how much the water
level rises
EQ: How do I define mass, weight and density?
Steps for the water displacement
method
• Record the volume of water in the
graduated cylinder
• Carefully place the irregular solid into the
water. Record the volume of the water
plus the object
• Subtract the volume of the water alone
from the volume of the water plus the
object
EQ: How do I define mass, weight and density?
Density
• The measure of how much mass
is contained in a given volume
• The density of a substance is
the same for all samples of that
EQ: How do I define mass, weight and
substance.
density?
The formula of density is:
Density = Mass / Volume
EQ: How do I define mass, weight and density?
Why is density expressed as a
combination of two different
units?
• Because density is actually made up
of two other measurements – mass
and volume – an objects density is
expressed as a combination of two
units
EQ: How do I define mass, weight
and density?
Two Common Units For
Density
• Grams per cubic centimeter (g/cm³)
• Grams per milliliter (g/mL)
EQ: How do I define mass, weight and density?
Math Practice: What is the
density of a wood block with a
volume of 125 cm³ and a mass of
57 g?
Density = mass / volume
Density = 57 g / 125 cm³
EQ: How do I
define mass,
weight and
density?
Density = 0.46 g/ cm³
Math Practice: What is the
density of a liquid with a mass of
45 g and a volume of 48 mL?
Density = mass / volume
Density = 45 g / 48 mL
Density = 0.94 g/mL
EQ: How do I define mass, weight and density?
An object
floats if it is
less dense than
a surrounding
liquid.
EQ: How do I define mass,
weight and density?
Densities of Some
Common Substances
Substance
Density
(g/cm³)
Air
0.001
Ice
0.9
Water
1.0
Aluminum
2.7
Gold
19.3
How could you use density to
determine whether a bar of metal is
pure gold?
• If the bar of gold
has a density that
is greater than or
less than 19.3
g/cm³, then the
sample is not pure
gold.
EQ: How do I define mass, weight and
density?
Densities of Some
Common Substances
Substance
Density
(g/cm³)
Air
0.001
Ice
0.9
Water
1.0
Aluminum
2.7
Gold
19.3
Will an object with a density of
0.7 g/cm³ float or sink in water?
• An object that has a density of 0.7
g/cm³ will float in water (1 g/cm³)
because it is less dense than water
EQ: How do I define mass, weight and density?