National Chemistry Week - Experiments - Hot Sips

THE AIM:

To observe hot water rise in cold water

WHAT YOU WILL NEED:

• 30 cm of string
• 1 small bottle
• 1 large jar
• food colouring

WHAT TO DO:

1. Tie the string around the neck of the small bottle.
2. Fill the large jar with cold tap water.
3. Fill the small jar with hot water and add a few drops of food colouring.
4. Use the string to carefully lower the small jar into the larger jar.
5. Make observations.

Hot water weighs less than cold water, for equal volumes. This is what causes the hot water to rise to the top of the cold water.

This experiment can also be done using cold water both in the large and small jars. Another variation is to reverse the first experiment by using warm water in the large jar and cold water in the small jar. The water in the small jar should be coloured with food colour in all three experiments to help see the effects. The class can make observations for all three situations.