Comet Facts for Students
'Comets are extremely old, icy and oddly shaped objects in our solar system. They are exciting for a few reasons:
-- Since ancient times, humans have observed comets in the sky. Roughly once every 10 years, we can see a comet from Earth with the unaided eye. Its impressive tail blazes across the sky over the course of several days or weeks.
-- Scientists think comets hold pristine materials within them that date back to the formation of our solar system.
-- Many scientists believe that comet impacts delivered water and other important building blocks for life to the early Earth. '
This site has a lot of information about comets as well as links to other resources.