Direction-Changing Arrows

Since school has started and I find myself with less free time, I now appreciate the simpler science experiments. This experiment is very simple, but it still has a really cool final result. I hope you enjoy it as much as I did.

What you need:

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

Steps:

  • Draw 2 arrows facing the same direction on the sheet of paper.
  • Place the glass of water in front of one of the arrows and watch as the image of the arrow flips around.

What makes the arrow flip?

In this experiment, light traveled through the air, the glass jar, the water, and then back through the air before hitting the drawing of the arrow. Whenever light passes from one medium to another, it refracts, or changes direction. Water also acts as a magnifying glass. When light goes through a magnifying glass, the light bends toward the center. The spot where all the light comes together is called the focal point. Beyond the focal point, the image appears to reverse because the light rays that were bent pass each other and the light that was on the right side is now on the left and the left on the right, which makes the arrow appear to be reversed. The diagram below helps explain this concept well.

convex lens tree

“Physics in a Glass: Reversing Arrows.” PhysicsCentral, American Physical Society, www.physicscentral.com/experiment/physicsathome/reversing-arrows.cfm.

3 comments

  1. Tarquinio

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  2. Lorrine

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