1.0 EXPERIMENT 3.6 – Understanding the Concept of Density

2.0 Aim : To study the density of solids and liquids.

3.0 Material : water, cork, sand, petrol, nail

Apparatus : 100 ml measuring cylinder, beaker

4.0 Procedure :

1. I put water, petrol, sand followed by the cork into the

measuring cylinder.

2. I drew what I observed .

5.0 Observation :

i) Cork, sand, water and petrol are matter.

ii) Based on the substances used, examples of:

a) solid: cork, sand

b) liquid: petrol, water

iii) cork and petrol floats on water; while sand sinks in water

iv) The density of these substances affect their buoyancies.

v) The cork sinks when a nail is added to it because it becomes denser. 6.0 Discussion and analysis.

6.1 i) Cork/petrol floats on water because it is less dense than water

ii) Sand sinks in water because it is more dense than water

iii) Cork float on petrol because it is less dense / Water sinks in petrol

petrol

water

cork

sand

because it is more dense than petrol

iv) Sequence of densities of substances in ascending order:

Cork petrol water sand.

6.2 i) The buoyancy of a substance depends on its density

ii) A less dense solid/substance floats in a more dense liquid.

iii) A denser/ more dense substance sinks in a less dense liquid.

6.3

Substance Density [gcm-3]

Cork 0.25

Petrol 0.75

Ice 0.92

Water 1.0

Sand 2.6

Mercury 13.6

i) Using the results and Table 1, the position of ice and

mercury are predicted if all the substances were put together in a gas jar.

Glass

Ice cube

Cork

Petrol

Water

Glass

Ice cube

Cork

Petrol

Water

Sandmercury

6.4 i) Based on the results and table of densities, the substances are

classified into two groups based on the common property:-

Float on water Do not float on water

Cork Sand

Petrol Mercury

Ice

ii) Another criteria we can use to group the substances is buoyancy of

substance in petrol.

Float on petrol Do not float on petrol/sink in petrol

Cork Water

Ice

Sand

Mercury

7.0 Conclusion:

Different substances have different densities.