How does a lens form an image? See how light rays are refracted by a lens. Watch how the image changes when you adjust the focal length of the lens, move the object, move the lens, or move the screen.

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

This article describes how to help students engage with nonfiction text by asking questions, identifying facts, making connections, and reflecting on the text. A template for use with students is included.

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.

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.

Visualize the gravitational force that two objects exert on each other. Change properties of the objects in order to see how it changes the gravity force.

Move the sun, earth, moon and space station to see how it affects their gravitational forces and orbital paths. Visualize the sizes and distances between different heavenly bodies, and turn off gravity to see what would happen without it!

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.

This video lesson highlights how science can be learned from daily life experiences. It emphasizes the ways in which simple laws of physics can be understood from personal observations and experiences, and in fact it demonstrates that we use these laws as if they were built into our instincts. The video also introduces Newton's laws of motion. The title, Gravity at Work, comes from a fascinating example of two laborers working at a construction site in Pakistan. In this lesson, Newtonian equations of motion are used to determine the velocities and height achieved by the projectile in a very simple and basic manner.

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.

How do greenhouse gases affect the climate? Explore the atmosphere during the ice age and today. What happens when you add clouds? Change the greenhouse gas concentration and see how the temperature changes. Then compare to the effect of glass panes. Zoom in and see how light interacts with molecules. Do all atmospheric gases contribute to the greenhouse effect?

Metals are grouped according to their characteristics. This video segment uses the periodic table for an in-depth discussion.

This expository article, written for students in grades 4-5, explains why ice floats and how this is essential to life on earth. Modified versions are available for younger students.

In this ZOOM video segment, join Hana as she learns traditional Japanese drumming with her Taiko group.