A spectrometer is used by researchers in all fields to split light into its constituent parts, and analyse all sorts of signals from solar radiation and absorption from space dust to the changes in molecules on a super duper short time scale.

If thinking about all that made you hungry, then you’re in luck! Finish off your breakfast cereal and turn the left over box into your very own spectrometer!


What you’ll need

1 Cardboard box (cereal boxes make it extra novel)
1 Compact Disk (CD)
Duct tape
1 Craft knife
1 pair of scissors
1 ruler
1 protractor


Cut away the opened flanges on the top of the cereal box (where you got your cereal from)

On the closed end, draw a line that makes a 60 degree angle with the base of the box like so

With the box oriented as above, cut along the line you just drew, starting from the top right hand corner, and stopping 10 cm along. Do the same on both sides of the box. This is where the CD will go in the end.

With the underside of the CD facing the open end of the box, slot that into the slits we just made. The light will come in from the open side and hit the underside of the disk, where it will be dispersed and reflected upwards. Right now, you won’t see that because the top of the box is closed.

Cut a viewing port using your pair of scissors by cutting along the green lines (below) and folding the flange up


The last thing we need to do now is to make a slit: the slit in a spectrometer is one of the key components and allows us to distinguish between the components of light and stops it from becoming one big blur. We can do this by taking a piece of the flange we cut off in the first step, and cutting a line in the card board. Push the blade all the way through so that it’s wide enough to let light through, and make sure to get rid of those pesky whiskers of paper that will muck up your image.

Use duct tape to fix that piece so that when you look through the slit, you see the surface of the disk we have inserted.

Close up all the gaps with duct tape, and tape your CD down. Now you should have a nice CD spectrometer to play with. Try looking at the sun, and you’ll see something like this.

solar_spectrumDo you know what the dark lines you’re seeing are? Try looking at some room lights, or look at things through some pieces of colored cellophane. What happens?



Excellent guide on how to make one and what to do with it