Measuring volume
To calculate The density of a material is the mass of 1 cm3 (or 1 m3) of the material. It is a measure of the compactness of a material. Density is measured in grams per centimetre cubed (g/cm3) or kilograms per metre cubed (kg/m3)., the The volume of a three-dimensional shape is a measure of the amount of space or capacity it occupies, eg an average can of fizzy drink has a volume of 330 cm3. of the material must be known.
If the object is a regular shape, the volume can be found by measuring length, breadth and height and using the equation:
Volume = length x breadth x height
If the object has an irregular shape, the volume can be measured using a measuring cylinder or a displacement can.
Volume of stone = Final Volume 鈥 Initial Volume
Volume of stone = 75 cm3 鈥 50 cm3 = 25 cm3
If the mass of the stone is measured using a top pan balance and found to be 175 g.
\(\rho = \frac{m}{v}\)
\(\rho = \frac{175~g}{{25~cm}^3}\)
Density of the stone is 7 g/cm3
The volume of larger irregular objects can be measured using a displacement can.
- Place the stone on the top pan balance and measure its mass.
- Fill the displacement can until the water is level with the bottom of the pipe.
- Place a measuring cylinder under the pipe ready to collect the displaced water.
- Carefully drop the stone into the can and wait until no more water runs into the cylinder.
- Measure the volume of the displaced water.
- Use the measurements of mass and volume to calculate the density of the stone.