You now have a finished CD spectroscope. The way to use it is to hold a light source up to the slit on the top, and look inside the container through the notch. You should see a very clear strip of rainbow color running from the center hole of the CD to the notch. Move the light source around to see what angle gives the best spectrum. Try other sources of light.
Different light has different color strengths.
If you have trouble seeing the spectrum of some specific light, try going into a dark room and having the light you are testing being the only light. What is happening A spectroscope is a device that separates light into its component colors. The way a spectroscope does this is to make use of something called a diffraction grating. Light reflects and refracts through this diffraction grating, and the different colors of the spectrum all reflect and refract a little differently. This is how the colors are separated into the colors of the rainbow.