Optics was one of my favorite parts of my physics education. The idea that light is both reflected and refracted by interfacing with a new material in its path is very cool. The fact that different wavelengths of light refract at different angles (e.g. rainbows, prisms) is beautiful, both for the aesthetic value and for the information is can reveal about the source of the light.

I wanted to share that fun with my kid so I built this little “laser rake” from some cheap laser pen modules and a 3d printed case. By having multiple beams, you can see the way the different angles at which the laser hits the lenses have different effects on the beams. This was one of the more successful little projects we’ve done together.