Comets and Meteors. Sp a ce - Level 1 and 2. Concept This lesson introduces the students to comets and meteors.

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1 Concept This lesson introduces the students to comets and meteors. Comets From nineplanets.org Comets are a mixture of ices (both water and frozen gases) and dust that did not get incorporated into planets when the solar system was first formed. This makes them very interesting as they give us clues to the composition of the solar system when it was first formed. 878 comets have been cataloged and their orbits at least roughly calculated. When they are near the Sun, comets have several distinct parts: nucleus: relatively solid and stable, mostly ice and gas with a small amount of dust and other solids; coma: dense cloud of water, carbon dioxide and other neutral gases that are vapourised from the nucleus; dust tail: up to 10 million km long composed of smoke-sized dust particles driven off the nucleus by escaping gases; this is the most prominent part of a comet to the unaided eye; ion tail: as much as several hundred million km long composed of plasma with rays and streamers caused by interactions with the solar wind. Comets are invisible except when they are near the Sun. Most comets have highly eccentric orbits which take them far beyond the orbit of Pluto; these are seen once and then disappear for millennia. Only the comets with short and intermediate orbit periods (like Comet Halley) stay within the orbit of Pluto for a significant fraction of their orbits. Sp a ce - Level 1 and 2 Meteors From starchild.gsfc.nasa.gov A meteoroid is a piece of stone-like or metal-like debris which travels in outer space. Most meteoroids are no bigger than a pebble. If a meteoroid falls into the Earth's atmosphere, it will begin to heat up and start to glow. This is called a meteor. If you have ever seen a "falling star", you were actually seeing a meteor. Most of the original object burns up before it strikes the surface of the Earth. Any leftover part that does strike the Earth is called a meteorite. A meteorite can make a hole, or crater, in the ground when it hits it. The larger the meteorite, the bigger the hole. 1 of 5

2 Materials and Equipment Comets worksheet Parts of a Comet worksheet What s the Difference between Meteoroids, Meteors and Meteorites? worksheet Procedure Students use internet and library resources to complete the three worksheets. Explanation Students use and build on the knowledge they have to research and complete the worksheets. The results can be discussed as a class. Sp a ce - Level 1 and 2 2 of 5

3 Comets Worksheet Every comet takes a to make a orbit. C O M E T S Comets are another part of our. They look like a fuzzy star with a long and a rocky. They are made up of frozen gases, and. amount of time One famous comet called Comet takes about years to once around our sun. 77 different tail Halley s dust ice orbit head full solar system 3 of 5

4 Parts of a Comet Worksheet Parts of a Comet Look at the picture of the comet and place the letter that you think best matches the description of the comet part. Nucleus The smaller glowing area within the comet made of rock, ice and frozen gas. Tail of ionized gases The solar wind pushes the ionized gas away, sometimes looks more "bluish" and more like a thin straight line away from the sun. Tail composed of dust Radiation pressure pushes the dust directly away from the Sun, sometimes more "yellowish" and is more spread out. Coma This is the glowing head formed as the Sun vaporizes the frozen gases. 4 of 5

5 What s the Difference between Meteoroids, Meteors and Meteorites? worksheet 5 of 5