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.

Acids and Bases: Testing Rocket Cars

In this ZOOM video segment, cast members make bottle rocket cars using lemon juice and baking soda, and experiment with different ways of launching the cars.

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Acids and Bases: Testing Rockets

What happens when you mix baking soda and lemon juice? Watch the ZOOM cast launch a rocket using kitchen chemistry.

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Aerodynamics: What Causes Lift?

How does an airplane stay aloft when upside down? This media-rich essay from the NOVA Web site offers an explanation based on Newton's third law of motion.

Air Is Matter

This collection of still images presents different ways to visualize air, from billowing sails to windblown hair to tornadoes.

Air Power: Experimenting with Balloons

In this video segment adapted from ZOOM, cast members experiment with the amount of air expelled first from a balloon, then through a straw attached to it, and see how both affect a balloon's behavior.

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Air Power: Making a Hovercraft

In this video segment adapted from ZOOM, cast members make their own hovercraft and demonstrate how the air leaking out of a balloon can make a plastic plate hover above a table.

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Amplitude

This interactive activity adapted from the University of Utah's ASPIRE Lab shows how a pendulum's amplitude changes as you set it swinging from different distances from its axis, and how the amplitude of a sound wave changes as you adjust the volume.

Arch Bridge

This video segment adapted from Building Big illustrates the strength of the arch in bridge design and construction.

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The Art of Forces and Motion

Students learn about Forces and Motion by creating art that helps them to visualize, identify and explain these phenomena.

Astronauts in Hard Hats

This media-rich series of interviews from the NOVA Web site explores the unique challenges faced by astronauts doing construction work in outer space.

Astronauts Speak: Gene Cernan

In this audio resource from NOVA, astronaut Gene Cernan recounts his harrowing experience during America's first attempt to do work in outer space.

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Atmospheric Pressure

Did you know that air has weight? This illustrated essay from the NOVA Web site explores conditions that affect air density and atmospheric pressure.

Bandwidth and Data Conversion

This interactive activity adapted from the Wisconsin Online Resource Center describes the factors that affect the speed of data transfer in computer networking systems and some of the techniques used to increase the data capacity of these systems.

Basketball Physics

In this video from DragonflyTV, Jai and Jonathan track, graph, and analyze the motion of basketball shots as they investigate what factors influence the accuracy of their game.

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Beyond Einstein

NASA scientists describe some of the ways current science is addressing several of Einstein's fundamental questions and theories in this video adapted from NASA.

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Birth of a Supernova, Type Ia

In this interactive activity from NOVA Online, learn about a type of exploding star — a Type Ia supernova — that is so bright that astronomers can measure the distance to the galaxy in which it resides, and even learn which elements make up the star.

Birth of a Supernova, Type II

In this interactive activity from NOVA Online, learn about a type of exploding star — a Type II supernova — that is so large it has a mass 10 times greater than the mass of our Sun.

Booming Sands

This video segment, adapted from NOVA scienceNOW, presents basic concepts of physics behind "booming" sand dunes. See how surface tension affects potential and kinetic energy and how it all works together to create sound.

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Bouncing Science

In this lesson, based on the Science Friday segment Physics of Basketball, students explore the properties of various balls from different sports, and discuss why the design of each ball is suited to its associated sport.