Find a Compact Disk. find a white light source and see if you can convince yourself that you are looking at the reflection of the light source as seen in the first order m = 1 maxima where the tracks on the CD are acting to form a diffraction grating. Now estimate the tip angle required to move the reflection from the color "violet" to the color "red". Use the grating equation m? = d sin ? to estimate the spacing between the tracks of a CD.