In this video segment adapted from NOVA, scientists use computer simulations to explore the question of how supercell thunderstorms produce tornadoes.

This video segment adapted from FETCH! shows contestants experimenting with different materials to see which is the best insulator and thus best able to keep the lemonade at their stand cool for customers.

Aaron and Justin investigate which sunscreen best keeps out harmful ultraviolet rays from the Sun, in this video from DragonflyTV.

This illustrated essay from A Science Odyssey Web site explains the science behind radio waves, including the role of electrons and electromagnetic fields.

In this video segment adapted from Shedding Light on Science, observe demonstrations of the fundamental idea that light travels in straight lines.

In this fast-paced NASA Brain BitesŒ_íěÖ video, an astronaut demonstrates the impact of microgravity on the use of tools in space.

In this video segment adapted from NOVA, follow novice runners as they train for a marathon, and discover how quickly the body responds to regular aerobic exercise.

In this video segment adapted from NOVA, explore the theory that small bits of gas and dust combined to form protoplanets billions of years ago, which in turn collided to create the four rocky planets of the inner solar system.

In Blazing a Genetic Trail, by the Howard Hughes Medical Institute, follow this three-step approach to treating genetic diseases.

This video segment adapted from the Space Telescope Science Institute shows what the Hubble telescope found when it stared at a single, nearly empty spot in the sky for 10 days in 1995. The unexpected result was a picture of a multitude of galaxies stretching into the distance.

Students learn how the human body self-regulates to maintain a stable internal environment despite changes in the external environment.

In this video segment adapted from NOVA: Judgment Day: Intelligent Design on Trial, learn how modern genetics and molecular biology offer compelling support for evolution. The video features an interview with biologist Ken Miller.

This video segment from NOVA: "Cracking the Code of Life" looks at the meaning and significance of the effort to decode the human genome.

In this video segment adapted from the National Film Board of Canada, learn how the Inuit people have used their traditional knowledge to understand and adapt to changes in their Arctic environment, particularly when hunting and navigating the landscape.

In this video segment from The Secret of Life Teaching Modules: "Nothing to Sneeze At: Viruses," watch as a virus attacks a cell, and learn how the immune system reacts to this onslaught.

This video segment adapted from A Science Odyssey looks at the invention of the automobile and the development of mass production.

This video segment adapted from A Science Odyssey looks at the invention of nylon.

This video segment adapted from A Science Odyssey considers modern technology's impact on society.

In this video segment adapted from NASA, astronomer Michelle Thaller introduces the world of infrared light and demonstrates how infrared cameras allow us to see more than what the naked eye can perceive.

This video segment adapted from NOVA illustrates why carbon is at the center of life on Earth. It also asks whether carbon-based life might exist on other planets.