Introduction

Procedure

• Gather these items from your home or workplace:
  • a glass of water
  • a pencil
  • a glass eye dropper or glass stirring rod
  • Wesson oil (regular, not lite)

• Looking from above the glass, place the pencil into the water and notice any changes to its appearance.

• Also look at the pencil from the side of the glass and up towards the water surface.

• How can you explain this phenomenon? Of course, you're saying to yourself, it's just light bending in the water. But is light really bending as it goes through the water? Where exactly does the light bend?

• Plus, which way is the light bending if you see the pencil with a kink in it? Draw yourself a diagram showing the pencil and how light from the pencil gets to your eyes.

• Pour the water out of the glass and replace it with some Wesson oil -- deep enough to submerge the eyedropper.

• Squeeze the air out of the eyedropper and place it in the oil. Watch the eyedropper as you release the bulb and let the oil up into the dropper.

• What happens to the eyedropper as the oil is sucked up into it? How can you explain this phenomenon?

• You can also try out the Java applet below that lets you manipulate a light beam entering different materials.

Go to the Refraction Readings when you're done with this Activity.