Introduction to Density
What is density?
 Density
is a specific property of
matter that is related to the mass
divided by the volume
What is the formula for density?

D = _Mass_
Volume

D=M
V

D = Density
M = Mass
V = Volume


M
D
V
Why does a penny sink in water?
 Pennies
are
more dense
than water,
therefore they
sink
Why does ice float in water?
 Ice
cubes are
less dense than
water, therefore
they float
How will an egg float in water?
 Egg
in fresh
water
–
The egg will
sink because it
is more dense
than the fresh
water
How will an egg float in water?
 Egg
in salt water
– The egg will
float because it
is less dense
than the salt
water
How will an egg float in water?
 Egg
in fresh and
salt water
–
The egg will be
suspended in the
middle because it
is the same
density as the
water mixture
Calculating Density
1 Frank has a paper clip. It has a mass of 9g and a volume of
3cm3. What is its density?
2. Frank also has an eraser. It has a mass of 3g, and a volume of
1cm3. What is its density?
3. Jack has a rock. The rock has a mass of 6g and a volume of
3cm3. What is the density of the rock?
4. Jill has a gel pen. The gel pen has a mass of 8g and a volume of
2cm3. What is the density of the rock?
How Do We Calculate Density in
3 Easy Steps?
 Step
1
– Calculate the
mass of your
object using the
triple-beam
balance
How Do We Calculate Density in
3 Easy Steps?
 Step
2
– Calculating the volume of a regular
solid
Measure the length, width and
height and use the volume formula
(V= L x W x H)
How Do We Calculate Density in
3 Easy Steps?
 Step
2
– Calculating the volume of an
irregular solid
Use the graduated cylinder for the
water displacement method
How Do We Calculate Density in
3 Easy Steps?
 Step
3
– Use the density formula
D = _Mass_
Volume
Water Displacement Method

Meniscus: The meniscus is the curve in the
upper surface of a liquid close to the surface of
the container or another object, caused by
surface tension
Measure
here!
Water Displacement Method
Examine the graduated
cylinders. What must the
volume of the rock be?

Measuring Mass on a TBB
What are the two triple beam balances reading?
Place these items in order of
density from least to greatest
E
C
E
C
A
D
B
A
D
B
Summary
1.
2.
3.
4.
5.
What is density?
Is Ice more or less dense than water? Why?
Name an item that is more dense than water.
Why does an egg float in salt water?
How can we calculate the density of common
items?