National Chemistry Week - Experiments - Guessing Game

THE AIM:

To demonstrate the difference between objects that sink and float.

WHAT YOU WILL NEED:

• objects that will sink in water as well as objects that will float

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  • some suggestions:
    
  • aluminum foil ball
  • aluminum foil boat
  • buttons
  • pumice stone (e.g. from stone-washed jeans)
  • plastic cap from a bottle
  • clay boat
  • chalk
  • clay ball
  • rock
• water table or large shallow bucket
• water

WHAT TO DO:

1. Ask the children to guess which objects will sink or float.
2. Place the objects in the water.
3. Make observations.

If they are the same size, heavier objects sink and lighter objects float. The pumice stone floats because it is full of tiny air bubbles. This is what makes it very different from other rocks. Air trapped in duckling's feathers helps them float.