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Fun Science: Optical IllusionMaking Change
Scientists use optical illusions to study how the brain allows itself to be tricked. Can you be fooled? Try an experiment and see.
You will need
Coin Two coins

Here's How
Between your thumb and index finger, hold two coins on top of each other. Then quickly slide the coins back and forth. You will see a third coin!

Why?
Everything you see is actually light reflected from objects. Your eyes use the light to create images on your retinas—light-sensitive linings in your eyeballs. Images don’t disappear instantly. So when something moves very quickly, you might see the object and an afterimage of it.

Try another illusion trick.

Text by Julie Vosburgh Agnone
Art by Gregg Valley

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