2 Solids are often very dense -
have a high mass for a certain
volume
3 Unit: kg/m cubed
3.1 grams/cm cubed
4 Example: A piece of iron has a
mass of 390 kg and a volume of
0.05 metres cubed. What is its
density
4.1 390kg / 0.05 metres cubed
4.1.1 = 7800 kg/m cubed
5 The volume of a regular object can be
calculated by multiplying its length x
width x height
5.1 Irregular: Using a displacement
can and a measuring cylinder
6 Displacement:
6.1 Find the initial water level: 60
milliliters or 60 cm cubed
6.1.1 Put the object in the water and find the
FINAL water level: 72 milliliters or 72
cm cubed
6.1.1.1 Volume of cylinder = Final - initial = 12 cm3
7 Pressure under a solid
7.1 Pressure (in Pascals) = Force (in
Newtons) / Area (in square meters
8 Pressure in Liquids
and Gases
9 Magdeburg Hemispheres
9.1 2 large bowls put together and then pumped the air
out. The bowls could not be pulled apart, even when
attached two teams of horses to the bowls.
10 Pressure and Depth
10.1 The force at the bottom of the column is equal to all the weight of water above it. The volume
(V) can be found by multiplying the area of its base (A) by the height (h) of the column.
10.1.1 The mass can be worked out by multiplying the volume by the density (p)
10.1.1.1 Volume = Area of Base x Height of Column
10.1.1.1.1 Mass = Volume x Density
10.1.1.1.1.1 Density = Mass / Volume
10.1.1.1.2 The force (F) on the bottom is equal to the weight of
this volume of water = which is mass x 10
10.1.1.1.2.1 Pressure Difference (in Pascals) = Height (in m) x Density (in kg/m3) x g (in N/kg)