Light waves travel in straight lines through empty space, but more interesting things happen to them when they travel through other materials, especially when they move from one material to another. That’s not unusual: we do the same thing ourselves.
Have you noticed how your body slows down when you try to walk through water? You go racing down the beach at top speed but, as soon as you hit the sea, you slow right down. No matter how hard you try, you cannot run as quickly through water as through air. The dense liquid is harder to push out of the way, so it slows you down. Exactly the same thing happens to light if you shine it into the water, glass, plastic or another more dense material: it slows down quite dramatically. This tends to make light waves bend, something we usually call refraction.
Watch the video to learn how plastic bottles are used to create light in buildings in the Philippines, and then make your own sunlight box with the power of refraction!
You will need:
A medium/large cardboard box
Empty plastic bottles
- Tape up the seams on your box so it is strong and no light can leak inside.
- Tape a large sheet of tin foil on the top.
- Fill two bottles with water.
6. Carefully put the bottles through the tinfoil and down into the two holes so that the bottles are hanging.
7. Look inside using the viewing flap.
8. Try placing food colouring into the water-filled bottles to create different light effects.
Send us a picture of your sunlight box so we can show them off on our site! 🙂
If you loved this activity, we encourage you to read about how to make things invisible using light!
Source image: Pinimg