Properties of Matter

Water Scales

Enrichment Activity for 5-11 11-14

What you need

  • Ruler
  • Pencil
  • Two cups
  • Water


  1. Place the middle of a ruler over a pencil.
  2. Put two cups with the same amount of water on either end of the ruler.
  3. Put your finger in the cup that is lifted.

Results and Explanation

As you put your finger in the water, the water tries to push up and float your finger. Because of this the finger pushes down on the water at the same time, causing the cup to tip.

These experiments have not been specifically safety tested for home use but we believe them to be safe if the instructions are followed. Adult supervision or direction is recommended as appropriate. All experiments are carried out at your own risk.

is a special case of Force
appears in the relation Upthrust = Weight of Displaced Liquid
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