This interactive feature from the NOVA "Surviving Denali" Web site details the variety of ways the body can fail while climbing a high-altitude peak.

Throughout the day, your nervous system monitors and makes endless adjustments to your body's basic systems -- all to keep you alive. This interactive feature illustrates the complexity of such a task.

Which part of your brain controls your ability to swallow? Your instinct to survive? And how do all the brain's parts function cooperatively? Find out with this interactive feature from the NOVA: "Coma" Web site.

This video segment from The Human Spark observes the brains responses to a series of cognitive tests.

In this interactive activity from the Building Big Web site, use your knowledge of bridge design to match the right bridge to the right location in a fictitious city.

In this interactive activity from Shedd Aquarium, build a fish and then release it into the reef to search for food and evade predators. Try different combinations and observe how each kind of fish has unique adaptations that help it survive in its habitat.

In this video segment adapted from ZOOM, the cast shows how the 34 steps in their Rube Goldberg invention use everything from gravity to carbon dioxide gas in order to accomplish one simple task: pouring a glass of milk.

In this video segment from ZOOM, Jillian explains how her simple machine uses marbles, levers, flowing sand, and a spinning wheel to water a plant.

How do you build a tunnel 32 miles long -- under water? This video segment adapted from Building Big, follows the construction of the Channel Tunnel (nicknamed "Chunnel"), the engineering wonder that connects England to France.

This illustrated demonstration from the NOVA Web site explains the concepts of buoyancy and density by showing what happens when different kinds of wood blocks are dropped in water.

This interactive brainteaser from the NOVA Web site challenges you to explain the behavior of a helium-filled balloon in a moving car.

This interactive brainteaser from the NOVA Web site challenges you to figure out what happens to the water level when a rock is resting in a boat and when it is submerged in water.

This interactive brainteaser from the NOVA Web site challenges you to figure out what causes an object to sink.

This video excerpt from NOVA’s Making Stuff: Cleaner and accompanying demonstration introduce students to the production and importance of bioplastics, or plastics made from plant or animal products.

In this media-rich lesson, students explore careers in science through profiles of Alaska Native scientists. They consider how traditional ways of knowing and Western approaches to science can complement each other and allow students to incorporate their own interests when considering careers in science.

In this video adapted from Texas Parks and Wildlife Department, learn about carnivorous plants that act as both producers and consumers in an ecosystem. See sundews and blatterworts capture and digest insects.

This interactive resource adapted from the National Park Service presents the key concepts of cave and karst systems, including how and where they form, different types, and various cave environments.

This interactive feature describes some of the most important structures and functions of the cell membrane.

In this interactive activity from NOVA, discover how centripetal force can affect you when riding in a car or flying at high speeds in a fighter jet.

This video segment explains centripetal force and illustrates how roller coasters rely on it to give you a thrilling ride.