Transcripts of 10116_Spectroscope_Assembly_H264_1280x720_30

Music Narrator: For this activity, I'm going to walk you through how to turn a paper towel tube into a spectroscope. You will need a paper towel tube, two roughly square pieces of aluminum foil, two strips of aluminum foil, a piece of diffraction grating, a pair of scissors, and some tape. We will start by constructing the end that goes up to your eye. For this end, you will need one of the aluminum foil squares. Fold it into quarters and cut of the corner where all the folds meet. This gives us the hole in the middle of the piece of foil when everything is unfolded. The diffraction grating, which looks like a piece of clear plastic with a rainbow sheen to it, is going to be taped over this hole, so the hole should be just a little bit smaller than the piece of diffraction grating. Be very careful to touch the diffraction grating as little as possible so you don't leave fingerprints on it. Tape the edges so that you're still able to see through the grating. Take the whole foil square and wrap it around one end of the paper towel tube so the piece of diffraction grating is centered over the tube end. It is more structurally stable if you put the tape on the inside. You can tape this into place immediately. Music Next we will construct the other end of the spectroscope. Take the other aluminum foil square and cut a hole in the center of it in the same way as before. Now take each of the strips of aluminum foil, and fold them lengthwise, taking care to give them a nice, sharp crease. Place them over the foil square, with the creased edges facing each other to create an open slit. The size of the slit should be about the thickness of a coin. Tape the two strips in place, keeping them nice and parallel. Music This foil square can now wrapped around the other end of the paper towel tube in the same way as before, but this time, do not tape it into place right away. When you look into your spectroscope, remember that it's the diffraction grating end that goes up to your eye. When you point your spectroscope at a light source you should be able to see a spectrum on the walls of the tube. While looking at a light source that produces a spectrum, rather than a continuous rainbow, rotate the slit end, which you have left untaped. You should see the spectrum change shape, going from a long, thin smear of color to a broad spectrum with clear lines in it, and back again. Find the point where the spectrum is as thick as you can make it, and all of the individual lines are clear and straight. When you have found this point, you can tape the slit end in place. Music

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