The Colors of White Light
For these six experiments we will use a diffraction grating to produce a spectrum of light for each of six different light sources. Our diffraction grating has 750 lines per millimeter. The diffraction grating works like the double slit experiment except the maxima produced in this experiment are considerably sharper than that of the double slit. During the experiment the angle of the diffraction grating will be manipulated by hand thus allowing a separation of the source light wave lengths resulting in a spectrum for each of the six light sources. We should observe spectra on both sides of the light source, that is to the left and the right of Ɵ=0 degrees. However we will only concern ourselves with the left side of Ɵ. All six experiments will be conducted in my home more specifically my laundry room. After Closing both doors and using a rolled up towel to block out all natural light coming in from under one door, I was able to create conditions similar to that of a dark room.
Procedure and results of experiment one (A clear incandescent light bulb):
For this experiment we will use a protractor, masking tape, our diffraction grating, and a small 1.5 inch clear incandescent bulb (wattage unknown). The bulb sits in a ceramic cup like housing which is used for heating scented wax. After allowing five minutes for the bulb to heat up we closed the doors and shaded the door cracks and began the experiment. We held the diffraction grating directly in front of the bulb at Ɵ =0 degrees approximately two feet away. Slowly panning the diffraction grating to the left produced an image of a continuous spectrum that appeared to be stretched horizontally. We could clearly see the entire visible light spectrum, violet being the least bright. Using masking tape we marked the wall behind the source light at about the spot where the image was projected through the diffraction grating. By placing the protractor at the location...