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How to Make an Underwater Magnifier

Because water and glass have a similar refractive index (the speed with which light travels through an object), a concave pool of water can act as a crude magnifier. This simple project will show you how to construct a magnifier that allows you to examine objects and animals living in shallow water without getting your feet wet. While its magnifying power will not be great, this can be a good project to teach children more about the underwater world.

Things You'll Need

Large tin can
Can opener
Sandpaper
Scissors
Clear plastic wrap
Heavy rubber bands
Water

Instructions

- 1
  Take both ends off the tin can using the can opener. Wash the can thoroughly.
- 2
  Sand the sharp edges off of the can using the sandpaper. Be careful not to cut yourself.
- 3
  Cut a piece of plastic wrap that is slightly larger than the end of the tin can. Lay it over one end, making sure there are no wrinkles, and fasten it to the tin can using a heavy rubber band.
- 4
  Turn the tin can over and cut another piece of plastic wrap. Fasten it to the end, but leave it loose so that it hangs slightly inside the can.
- 5
  Scoop water into the end of the tin can covered with the loose piece of plastic wrap. This is the end that will act as the magnifier.
- 6
  Place the magnifier into the water. Look through the end with the water in it.

Nature