The shared set of genes for body segments, possessed by all animals, are discussed in this video segment from Evolution: "Great Transformations."

In this video profile adapted from NOVA scienceNOW, learn about geneticist and rock musician Pardis Sabeti, whose innovative insights into natural selection demonstrated how beneficial mutations spread quickly through a population.

This ZOOMSci video segment teaches you how to germinate seeds in a plastic bag and helps you understand some of the factors that influence the germination process.

Learn how scientists regulate a nuclear reactor in this animation-enhanced essay from the FRONTLINE Web site.

This video segment, adapted from NOVA, chronicles the education of leading chemist Percy Julian. Although Julian began his elementary school years in the Deep South under Jim Crow laws, he became one of the few African Americans of his time to earn a Ph.D.

Featuring images of glacier formations, this interactive resource adapted from the National Park Service explains what glaciers are, where they are found, how they form, and how they move.

In this video adapted from the Encyclopedia of Physics Demonstrations, learn how a glass beaker vibrates at a specific frequency and how resonance can force it to shatter.

This video segment adapted from NOVA/FRONTLINE looks at the future of global warming as developing nations, including India and China, increase their need for energy.

Is the hydrogen car the answer to global warming? This video segment adapted from NOVA/FRONTLINE looks at the pros and cons of this developing technology.

This video segment adapted from NOVA/FRONTLINE examines the greenhouse effect, its role in keeping Earth habitable, and the industrial changes that have led to an increase in the planet's average temperature.

In this video segment adapted from Spanner Films, visit the Alaska Native village of Shishmaref, and learn how an entire town may be forced to relocate because of warmer temperatures, melting sea ice, and coastal erosion.

This video segment adapted from NOVA explores the effects of the Glen Canyon Dam on the beaches, wildlife, and vegetation of the Colorado River.

In this video segment adapted from NOVA, a fossil found among the Grand Canyon's rock layers reveals the existence of a shallow sea that once covered most of western North America.

This video segment adapted from NOVA features the youngest rock formations in the Grand Canyon, lava dams, and how they are subject to the eroding power of water.

In this lesson designed to enhance literacy skills, students learn how to read and interpret a distance–time graph.

In this video segment adapted from NOVA, watch residents of the Peruvian Andes build a suspension bridge made entirely of grass. The ancient Inca were a textile society and thus skilled in working with natural fibers including alpaca and cotton. Still, it might surprise people today that their solution to crossing the canyons and gorges of their mountainous empire featured another fibrous material: grass. When you consider how they built a simple suspension bridge, you'll realize that not only was this a practical solution, it was also a safe one. In this video segment adapted from NOVA, watch residents of the Peruvian Andes as they build a traditional and functioning grass bridge the likes of which enabled the ancient Inca people to flourish for several hundred years. Grades 3-12.

This video segment, adapted from NOVA, traces the evolving history of theories about gravity and a force that may oppose it, along with our understanding of the impact of both of these forces on our expanding universe.

In this video segment from NOVA scienceNOW, learn about the effects of gravity as astrophysicist Neil deGrasse Tyson falls through a virtual hole through Earth's center.

In this video segment adapted from NOVA, a meteorologist explains how an unusual weather pattern led to one of the most devastating floods of this century.

Learn about a study in which participants discovered contaminants in their homes, and how green chemistry may provide alternatives to such everyday toxins, in this video adapted from Contaminated Without Consent.