Activity time: 5 minutes

Materials for Activity

• A coin
• Adhesive putty
• A cup of water
• A non-transparent bowl

Preparation for Activity

• Set the coin in the middle of the bowl, at the bottom, using a small amount of the adhesive putty to keep it in place.

Description of Activity

This activity shows that sometimes our senses can be deceived, and what we see is not always what’s true.

Gather participants around the bowl close enough to see the coin at the bottom. Now have them move back, away from the bowl, until they cannot see the coin anymore.

Have someone pour the water very slowly into the bowl.

Watch the bowl from where you are standing.

What do you see? When the bowl is empty the edge of the bowl prevents you from seeing the coin. When the bowl is full, the light bends over the edge so you can see the coin.

Ask:

• Have you ever noticed that things at the bottom of a pool or river always look closer to the surface than they really are?

This is because of the way light is bent through water and is an effect of refracted light.