Density
physical
• Density is a _________
property of
matter.
• Density can be defined as the amount
matter in a given ________.
space
of ________
• Example:
Two objects have the exact same volume,
but one is made of more matter.
• Example:
Which has more mass, a kilogram of
feathers, or a kilogram of lead?
• Density is a physical property of a
substance that is used to identify that
substance.
Density
of Lead
Density
of Lead
Density
of Lead
• The size of the object does not
change the density. The density of
lead is always going to be the same.
• Relative density:
Matter that is less dense will float on
matter that is more dense.
• Calculating density:
If you know the ________
and
mass
volume of an object, you can find
________
its density.
The formula:
density = mass/volume
OR
D=
m
-----v
• Identifying your units!
The base unit for mass (m) of
an object is grams (g).
The base unit for volume of a
solid is cubic centimeters (cm3).
The base unit for volume of a
liquid is milliliters (ml)
• How to find volume:
Regular solid: a solid which the sides can
be measured using a ruler to get the
volume.
V= L x W x H
Irregular solid: a solid with sides that are not
capable of being measured with a ruler. Example:
odd shaped rock
For this type of object we use
WATER DISPLACEMENT
Water Displacement
To Find the volume of an
irregular solid:
1. Using a graduated cylinder fill with
water to a specific amount such as 100
ml.
2. Slowly lower object in to the
graduated cylinder (the water will rise).
3. Subtract the final amount from the
initial amount and that will be the
volume of the object.
4. Convert from ml to cm3.
Practice Problem 1
• A 800g rock has a volume of
8cm3. What is the density of
the rock?
Practice Problem 2
• A piece of wood that measures
3.0 cm by 6.0 cm by 4.0 cm has a
mass of 80.0 grams. What is the
density of the wood? Would the
piece of wood float in
water? (volume = L x W x H)
Practice Problem 3
• Archimedes was commissioned to
determine if the crown given to the
king was pure gold or not. If the crown
had a mass of 882 grams and displaced
50 mL of water, was the crown pure
gold?
• The density of Pure Gold is 19.3 g/cm3.