What is a solar eclipse and why are they only visible in some parts of the world? In this video segment adapted from NASA, astronomer Susan Stolovy uses animations to provide an answer to these questions.

In this video segment adapted from ZOOM, cast members assemble a solar still and make fresh water from saltwater, demonstrating two steps of the water cycle, evaporation and condensation.

In this lesson designed to enhance literacy skills, students study a disease outbreak and the investigation that followed to understand the role that public health workers play in protecting the communities they serve.

This interactive quiz from the NOVA Web site features an array of interesting facts about the nature of sound underwater.

This video segment, adapted from ZOOM, explores how sound waves travel differently through solids than through air, in this case, a metal clothes hanger.

This video segment adapted from Shedding Light on Science uses historical illustrations and everyday examples to show that light has a speed and does not travel instantaneously.

In this video adapted from the University of Alaska, Anchorage, Alaska Native people of Chevak teach visitors about the beauty of Cup'ik culture and the spirit of the earth, sea, and animals.

In this video profile produced for Teachers' Domain, meet conservationist Steve MacLean, an Inupiaq from Barrow, Alaska, who works to preserve the health of the Bering Sea ecosystem.

Take a journey back through time, using ice cores to learn about the Earth's climatic history. From the FRONTLINE/NOVA: "What's Up with the Weather?" Web site

This animation adapted from Garland Science Publishing takes a close look at the DNA double helix and its individual components, describing their chemical structures and how they function together to make the DNA molecule unique.

Studying life on the seafloor beneath Antarctica's thick ice is a major challenge for ecologists. Learn about a new device that can reach those icy depths in this video segment adapted from WomenInAntarctica.com.

This video segment from FRONTLINE/NOVA: "Harvest of Fear" explores genetic modification of salmon and possible consequences.

In this lesson designed to enhance literacy skills, students learn about the varied physical and behavioral adaptations that animals rely on to help them survive changing environmental conditions, such as the arrival of winter.

This video segment adapted from NOVA reveals how junk DNA helped solve an evolutionary mystery: Why do certain species of fruit flies have wing spots while others don't?

The peacock provides a classic example of sexual selection, the force behind nature's extravagances. From Evolution: "Why Sex?"

Bonnie Chen builds on students' prior knowledge of mutations to lead her class through a simulation of wading birds feeding.

Marilyn Havlik leads students through a simulation of the Hardy-Weinberg Principle to develop their understanding of population genetics.

This interactive activity from A Science Odyssey offers a historic tour of 20th century home technologies.

In this video adapted from KUAC-TV and the Geophysical Institute at the University of Alaska, Fairbanks, learn how tectonic plate movement is responsible for building mountains, such as the Wrangell and St. Elias Mountains.

This interactive activity produced for Teachers' Domain shows the relationship between tectonic boundaries and the locations of earthquake events and volcanoes around the world.