Light Sound and Waves

Reversing Glass

At home for 5-11 11-14

What you need

  • A glass of water
  • A piece of paper
  • A marker pen


  1. Draw a column of short arrows
  2. Hold the paper a little way behind the glass and look through the water at the arrows

Results and Explanation

The arrows should point in the opposite direction. The water acts like a glass lens, bending the rays of light and reversing the image of the arrows.

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.

can be analysed using Refraction Formation of Images
can be analysed using the quantity Focal Length Power of a Lens
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