Step 1: Materials Required
1 Plastic Glass
1 thin needle ( you can use anything which is pointed and has more thickness than the needle)
1 medium thickness nail
1 flashlight (mine was Blue LED based. I don't know whether ordinary bulb flashlight will work or not since for "Diffraction" and "Interference" to take place(on which my planetarium is based) you need a monochromatic light .Simply just use a LED flashlight.
Step 2: Assembly
Now make holes by needle on the foil covered glass. Then make holes using the nail. You can refer to pictures.
Step 3: How to Use
Try with different pattern of holes and every time a new galaxy will be born.
How it works:
It works on diffraction mainly which is distortion due to very small slits and holes which is due to the wave nature of light. Also the rough and reflective edges of aluminium foil also helps in reflecting and distorting the light creating a galaxy like pattern.
Check out other exiting experiments on http://scimad.com/