Density - Junction Hill C

• 1) Everything is made of matter.
• 2) The amount of matter we have is
called mass.
• 3) The space that matter takes up is
called volume.
• 4) The amount of matter we have in a
certain amount of space is called its
For example: You
have found a cube of
iron. To find its mass
you will have to
compare it to
something else
whose mass we
already know.
How do you think we
could measure its
That’s right, use a
Basically there are two ways to measure the
volume of an object.
It depends on its size and shape as to
which method you will use.
Also, the unit for volume is always
cubed. (cubic centimeters or cm3 )
• To find the volume of a regular shape like a cube or a shoe
box, all we have to do is measure its
– Length
– width and
– height
– then do some easy multiplication
If the Length= 6 cm, the Width = 4 cm
and the Height = 2 cm.
The formula for volume is:
Length x Width x Height = Volume
What is the volume of the box?
6 cm. x 4 cm. x 2 cm.= ?
• If you got 48 you left something out.
• It is very important give the unit of
measurement so everyone knows what
you are talking about.
• The correct answer is 48 cm3.
• Don't forget the unit is always cubed.
• There is another way to find the volume
of something and that is by using the
water displacement method. This method
is particularly good to use when you have
object that doesn't have a regular box
like shape.
• For this method you will need water and a
graduated cylinder.
• 1)Let's say you have a little object.
• 2) Fill a graduated cylinder with
enough water to cover the
• 3) Carefully lower the object into
the graduated cylinder so no
water splashes up on the sides.
• As the object goes into the water,
the water will be displaced and
go up.
• 4)The distance the water goes up is
the volume of the object.
What do you do if the object you
have is too large to fit into a
graduated cylinder?
1) Let's say you have found a rock.
2) Instead of putting the rock into a graduated cylinder,
you will use a beaker filled to the top with water.
3) You have to be very careful and put the rock in slowly.
4) Since the water will overflow make sure you place
a dish under
the beaker to catch the water.
5) After you have put the rock into the water and it stops
overflowing, carefully pour the water from the dish into
a graduated cylinder to measure the water.
6) Check the level of the water and you will have the rocks
• You have three containers of equal size, one
filled with cement, one filled with water, and
one filled with air.
1. Which container would have matter that is very tightly
2. Which container would have matter that is loosely packed?
3. What would happen if you put the cement, water and air
into one large container?
Take a look at the two boxes below. Each box has the same volume. If
each ball has the same mass, which box would weigh more? Why?
• The box that has more balls has more mass per unit of
• This property of matter is called density.
• The density of a material helps to distinguish it from other
• Since mass is usually expressed in grams and volume in
cubic centimeters, density is expressed in grams/cubic
We can calculate density using the formula:
Density= Mass/Volume.
• calculate the density of
two blocks.
• Block I
• Mass = 79.4 grams
• Volume=29.8 cubic cm.
• Block II:
• Mass= 25.4 grams
• Volume=29.8 cubic cm.
• What is Block I?
• What is Block II?