The purpose of this lesson is for students to explore the nature and composition of a comet. The student will select ingredients to create a comet and will learn to identify ingredients responsible for a comet nucleus, and how changes in the nucleus when the comet approaches the Sun cause two different kinds of tails to form. Students can explore some facts, myths, and legends linked to the appearance ... Full description.

In this classroom exercise, students will "build" a comet using representative materials. Learning outcomes, concepts, and a link to the comet "recipe" are provided. Safety tips, comet facts, and links to additional information are also included. Full description.

Students in this lesson will be introduced to the concept of tides and tidal forces. By viewing a related applet which visualizes the relationship between the Earth, moon and tides, students will gain an understanding of why the Earth experiences tides. In the process they are asked to observe and explain how the relative positions of Earth, the moon, and the sun are responsible for the moon phases, ... Full description.

This website presents the story of Comet LINEAR, which broke apart in 2000, revealing what many scientists thought all along - water in Earth's oceans could have come from outer space. The article discusses findings from the breakup of Comet LINEAR and the possibility of water in its composition. Full description.

This is a copy of a news story originally written on March 1, 2001 that describes the theory of how small comets may have been at least part of the source of the water on our planet. The site also offers links to the University of Iowa's Small Comets research site and information on the ground-based measurements that are used to identify these comets. Full description.

This article discusses the importance of water in supporting and sustaining life and focuses on why water, and solely in its liquid form, is so essential. The focus here is on the potential presence of water on Mars. Some of the physical and chemical properties of water are summarized, and their uniqueness is presented as the reason planetary scientists are on the lookout for water on Mars and elsewhere ... Full description.

This site presents clues to suggest that liquid water once flowed on Mars - raising hopes that life could have arisen there - but the evidence remains inconclusive and sometimes contradictory. Full description.

This lesson plan provides instruction to teachers for creating a glacier in the classroom to demonstrate how glaciation affects landforms. Learning objectives include student understanding that as glaciers move, they create a variety of patterns on landforms by a process called glacial scraping, that the scraping patterns left by a glacier depend on how the glacier moved over the landform, and that ... Full description.

Users can read about the discovery of ice on Earth's moon, which occurs in the form of ice crystals accumulated near the lunar poles. The discussion covers the use of the neutron spectrometer as a tool for detecting water by sensing the hydrogen it contains, some ideas on the origin of the ice, and the fact that water has been found elsewhere in the solar system (on Europa, Jupiter's fourth-largest ... Full description.

Researchers have identified approximately 140 individual impact craters on Earth. These craters probably represent only about 25 percent of those to be found. Assuming an equal rate of impact around the globe, many more craters remain to be discovered, particularly in remote land regions of our planet and in the oceans. This activity uses satellite images of several craters on the earth to study impact ... Full description.