The Bulk Density of a Brick

Water Displacement Method

Density

Density, ρ = Mass

Volume

The Greek symbol used for density is ρ which is pronounced “ro”.

Density

Mass is relatively easy

as the brick can be weighed in air

to give its mass (m1 gm)

Mass in air, m1 = 2138.0 gm

Density

Volume is more difficult

as the brick is quite a complicated shape,

it is not very evenly shaped

and it has quite a rough surface.

Density

However, the Volume can be calculated

by weighing the brick in air (m1 gm) and then weighing it fully immersed in water (m2 gm)

The mass of water displaced by the brick =

Mass in air (m1 gm) – Mass in water (m2 gm)

Mass in water m2 = 1030.2 gm

Density

The density of water, ρw, can be assumed

to be 1 gm/cm3

Hence, the volume of the brick is numerically the same as the mass of water displaced

Density

The density can now be calculated

Density, ρ = m1 x ρw

(m1 – m2)

DensityLet us put the numbers in for our brick

Density, ρ = m1 x ρw

(m1 – m2)

Density, ρ = 2138.0 x 1 g/cm3

2138.0 – 1030.2 = 1.93 g/cm3

As 1 g/cm3 is the same as 1000 kg/m3, the density can also be stated as 1930 kg/m3 which is nearly 2 Tonnes per m3