Instructions:

• Firstly pour some water into the clear plastic container.
• Then add the same amount of oil to the container.
• Leave this for a few minutes until the oil rises to the top of the container.
• This occurs because the oil becomes lighter than the water.
• Place the container in the freezer for a couple of hours.

After these couple of hours, you should see that the water is now on top of the oil.

Why?

Because the water is now a solid. As it expands when is freezes, it also becomes less dense than the oil.