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DIY Physics Experiment

Bending Light with Water

by Annie Furman

Although physics can be very challenging there are many aspects of it which can be quite fun.
A really easy and fun experiment you can do at home is one that shows properties of light, such as how it travels, refracts and even bends.

You will need:
A water bottle (or any clear container to hold water)
A laser pointer
Bucket or sink

1) Poke a hole in the side of your bottle/container approximately three inches away from the bottom of the bottle.
2) While holding the hole closed with either your finger or a piece of tape, fill up your bottle/container completely with water. (When you release your finger the water will pour out. This is where you will need to have a bucket or a sink.)
3) Hold your laser pointer directly across from the hole on the opposite side of the bottle. When you release your finger, you will see the light from the laser follow the path of the water as it pours out of the bottle.

The physics behind it:

According to Snell’s Law, the light from the laser will change its path upon encountering the water. The laser beam is therefore bouncing back and forth in straight lines inside the bottle, and accordingly inside the stream of water as it flows. This gives the illusion of bending light as it falls from the bottle.

Remember you may need to experiment with the exact position with the laser on the bottle to get the perfect effect. If you are having trouble seeing the light, turning off the lights in the room might make the effect clearer.

I hope you all have fun!!

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