This is one of the few times that students have an opportunity to touch what an object in the Solar System is kind of like. This demo is very popular and can be found all over the Internet. The materials that are needed are shown in slide show (plus 2 large cups of water). Mix the water, sand, 1 tablespoon of corn syrup, and a dash of ammonia into the bowl (see slide show). These are the main ingredients of a comet. Of course the temperature needs to be decreased dramatically. Dry ice, frozen carbon dioxide, will do this and is also an ingredient. The dry ice needs to be placed into the double heavy duty trash bags (see slide show). Use the hammer to crush the dry ice into a powder (see slide show). Then carefully pour the dry ice into the plastic bowl (see slide show). Using the gloves shape the mixture into a ball (see slide show). Carefully remove the comet and let students touch it. The comet really is the nucleus of the comet–the solid part. Explain to the students that the Sun’s energy heats up the ice to form the gaseous coma, which can be seen in this demo.
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