Materials Required
  • A plastic container
  • Water,
  • Cooking Oil
  • Refrigerator for freezing

How to do it

  • Pour water into the clear plastic container.
  • Pour some some cooking oil into the container.
  • Leave this for a few minutes to settle down.
  • The oil will rise to the top of the container because ,the oil is lighter than the water.
  • Now keep the container into the freezer for a few hours.
  • Remove the container from the freezer and observe.
  • The oil is now below the water.
  • Explain to the child that this is because Water becomes solid when freezing.
  • The water expands when it frozen and becomes less dense than that of the oil. 
  • This makes the water to rise to the top.

What is learnt

  • The density of substance varies with temperature.