Before we begin: Never
look directly at the sun ether with your eyes or with the spectrometer
that you will build.
There are several option to make a visible light spectrometer.
Each of the ones described here uses a piece of an old CD.
Follow this instruction guide link to learn how make a spectrometer
that can easily be attached to your Webcam or cell phone
camera. We recommend this one. You will use their software
to analyze photos of the spectra that you take.
This video describes spectroscope which is made from a cereal box.