Swedish Fishing

When you go swimming and look at objects in the pool, you might notice that they appear to be a different size than they really are. You may even notice that objects that are halfway in the water appear to be bent. This fun experiment shows you why this works.

Materials

  • Swedish fish
  • Water
  • Wooden kabob spears
  • Clear container (a jar, a glass, etc)

Directions

  1. Fill your clear container with water
  2. Drop a few Swedish fish into the jar. Look at the fish from the side of the container. Do they look the same size as they did in the bag?
  3. Now put the kabob spear into the water. Does the spear still look straight or does it look bent? Why do you think this is?
  4. Try to spear the fish. When you catch one, go ahead and eat it!

Explanation

The reason the kabob stick looked bent is because of a concept called refraction. When light goes from a thin substance to a thicker substance (or vice versa), it tends to bend and makes the image look skewed. Air is much thinner than water, so the kabob looked bent even though it was actually straight.

The fish were magnified because of the curved shape of your container. When the water is curved, it creates a convex lens that makes the image seem closer than it really is.