Ever see a rainbow and wonder where the colors are coming from? Or wonder why a person’s legs appear bigger or just off while standing in a swimming pool? With this two part “Simple Science Experiment,” you’ll learn about how light can refract or “bend” through different materials.

Materials

• Tall cup (one you can’t see through)
• Penny
• Tape
• Water
• Wax paper
• Fine print reading material
• Magnifying glass or a pair of prescription glasses (with parents’ permission)

Experiment #1: Reappearing Penny

Procedure 

1. Using a small piece of tape, adhere a penny to the bottom (center) of a non-see-through cup.
2. Stand in a place where you can see inside the cup but can’t quite see the penny at the bottom because the top of the cup blocks the coin from view.
3. While standing in this position, have someone start to fill the cup up slowly with water. Observe when you can spot the penny just with the addition of water.

Explanation 

Did you know you see things because light is bouncing off them? Refraction is the bending of something as it travels through a different material. This particular experiment addresses light bending but, other things, like sound waves and seismic waves (earthquakes), also refract. Light changes the angle at which it bends as it goes through air into water or vice versa. So as water fills the cup with the penny, the light ray from the coin is bent until it can then reach your eye.

Experiment #2: Wax Paper Lens

Procedure

1. Cut a piece of wax paper out; place it over some fine print.
2. Put a single drop of water on top of the wax paper and then place the paper on top of the print.
3. Watch how the letters change as you move the water drop over them.

Explanation  

As in the first experiment, water refracts the light going through it. It is acting as a magnifying lens and causing the light to bend out from the letters, making them appear bigger. Experiment with different sized drops of water. Does this change the size of the letters? Did you know this is how eye glasses work? The lens will bend the light and make images get bigger or smaller, depending on the prescription. If you have a magnifying glass or pair of glasses, hold them over a piece of paper with words on it to see how you can change the size of the letters. The curve of the glass will cause the light to bend or refract!

Want to experiment further? Ponder this… will using sugar water or salt water change how big letters get in comparison to what you observed with plain water? Good luck and keep experimenting!

Steve Davala is a middle school science teacher who likes to write and work with Photoshop. He has two kids and subjects them to these science activities as guinea pigs! Follow Steve on Twitter (@sdavala) or email him at steve.davala@gmail.com.