Here’s a simple science experiment that you can do at home with kids to explore the properties of light. This science experiment makes a pair of arrows change directions with nothing more than a glass of water.
Magic Direction Changing Arrows Experiment
To start off, get a Post-It pad and some markers.
Draw two arrows on the Post-It pad, one pointing to the right and the other pointing to the left. We recommend drawing short arrows for this experiment.
Once you are done stick the Post-Its on the wall.
Fill a glass full of water and place it in front of the Post-It pad. Move the glass of water back and forth until you see the arrows magically change direction.
The arrow pointing to the right will appear to point to the left. The arrow pointing to the left will look as if it is pointing to the right.
The Science Behind It: Refraction
Why do the arrows change direction?
Travels at different speeds through different types of medium. It is fastest in air and a little slower in water. When light passes from one medium to another, e.g. from air to a glass of water, it is bent. This is a scientific concept known as refraction.
What is happening with the direction changing arrows is that the image of the arrow passes into the glass of water and is bent. This causes it to cross-over and comes out from the other side reversed.
Hence, we see the arrows changing direction. Science!