What is in a comet? Some scientists call it a "dirty snowball in space". With adult supervision, you can make your own comet with a mixture of materials that might surprise you. The resulting lump makes a comet tail of melting gases when you hold it up to a lamp in a darkened room. Try it yourself with our step-by-step instructions and guided scientific questions available in the downloadable support materials, or on the Science-U.org website.