AC / DC: What's the Difference?

This animated essay from the American Experience Web site explains the difference between alternating and direct electric current and offers in-depth explanations about the role played by a battery, light bulb, wire, and generator.

Diamonds: The Science Behind the Sparkle

This illustrated essay from the NOVA Web site explains why the atomic structure of a diamond slows down light and produces a sparkle more brilliant than from any other colorless substance.

Everyday Radiation

How much radiation are we exposed to every day? Find out in this video segment adapted from FRONTLINE.

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Geometric Optics

This interactive simulation adapted from the University of Colorado's Physics Education Technology project illustrates how lenses refract light to form images. Manipulate the object, screen, lens, and focal length and observe how the image adjusts.

Hoover Dam and Hydroelectric Power

How does a dam generate electricity and what are the environmental impacts of operating these mammoth structures? Find out in this video segment adapted from Building Big.

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Imaging with Radar

This interactive activity from NOVA features synthetic aperture radar (SAR), which uses radio waves to create high-quality images. Examine SAR images of Washington, D.C., and learn about this technology's unique advantages.

Infrared: More Than Your Eyes Can See

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.

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Laser Waterfall

In this video from the Encyclopedia of Physics Demonstrations, observe how a laser beam is trapped in a water jet because the light reflects against the surface of the water.

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Lightning!

This video segment adapted from NOVA explains the mysterious force of lightning.

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Lightning Hunters

Find out how scientists and engineers use rockets to attract lightning in this video segment adapted from NOVA.

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Mapping Magnetic Fields

This video adapted from NASA explains how a magnetometer determines magnetic fields around planets.

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Observing Refraction of Light

This video segment adapted from Shedding Light on Science illustrates how light changes speed, and thus direction, in a process known as refraction.

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Primary Colors of Light and Pigments

In this interactive activity adapted from Shedding Light on Science, discover the difference between the primary colors of light and the primary colors of pigment—and the connection between the two.

Radio Waves & Electromagnetic Fields

In this interactive simulation adapted from the University of Colorado's Physics Education Technology project, explore how a radio transmitter broadcasts electromagnetic radiation.

Refraction of Light Demonstration

In this interactive activity featuring videos adapted from the Rutgers PAER Group, observe how light bends when it travels through a convex lens, a concave lens, and glass.

Smart Power Grid

This video segment adapted from NOVA scienceNOW provides an overview of the existing United States power grid, and envisions a "smart" power grid that would prevent problems, such as blackouts, and reduce energy waste and pollution.

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Speed of Light

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.

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String Theory: A New Picture of Gravity

This video segment from NOVA describes the general theory of relativity and the theory of electromagnetism.

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Tour the Electromagnetic Spectrum

Take NOVA's interactive tour of the electromagnetic spectrum and find out why your eyes are like antennae for a narrow band of electromagnetic radiation.