Have you ever wondered how to make a rainbow? Build this spectroscope and find out how!
What you’ll need:
Empty paper towel roll
Scissors or craft knife
Blank or old CD
Small piece of cardboard or cardstock
Paint or stickers (to decorate)
What to do:
If you decided that you want to paint your paper towel roll, do this first and allow it to dry.
This next step is for adults only! With your scissors or craft knife, cut a small slit at a 45 degree angle near the bottom of the paper towel roll. Next, cut out a small hole, just large enough to look into, directly across from the slit you just made.
Place one end of your paper towel roll on your cardboard or cardstock and trace around it. Cut it out.
Now, cut a small rectangle into the center of that cardboard or cardstock circle.
You can now tape this circle onto the top of your spectroscope.
Place your old or blank CD into the slit near the bottom of the spectroscope with the shiny side facing up.
Your spectroscope is now complete! Use it outside, with the top facing the sky and look into your viewing hole. You will see a rainbow!
Why does this happen?
Because the CD is a mirror with spiral tracks over the surface.
Because these spiral tracks are evenly spaced apart, they separate colours making a rainbow!