This video segment adapted from the Atmospheric Radiation Program explains the differences in the formation of tropical convective cloud systems over islands and over the ocean.

In this video segment adapted from ZOOM, two solar cookers are tested against a control to see which can cook a "s'more" faster.

In this video segment, ZOOM guest Cassie takes us on a tour of the coral reef near her home in Key Largo, Florida, and points out some of its unique features.

This video from NASA features the Cosmic Origin Spectrograph (COS), which allows scientists to use spectrographic analysis to assess the composition of intergalactic material.

In this video excerpt from NOVA, find out how whole genome sequencing saved the life of Alexis, a fraternal twin who was originally diagnosed with cerebral palsy but, in fact, had an even rarer genetic condition.

This interactive activity from ChemThink takes a closer look at a covalent bond--how it is formed and how the sharing of two electrons can keep atoms together.

Students learn how DNA fingerprinting has been used in criminal investigations and discuss the limitations of and problems with DNA testing.

In this interactive activity from the Building Big Web site, investigate dams in distress and decide if they should be repaired, removed, or left alone.

This video segment from Evolution: "Darwin's Dangerous Idea," together with interviews with Daniel Dennett and James Moore, depicts Darwin struggling with publicizing his revolutionary theory.

In this video segment adapted from NOVA, scientists search for carbonized remains of plants preserved in lava flows to find out how long it has taken rain forests on Hawaii to regenerate after a volcanic eruption.

This video segment, adapted from Decision in the Streets by civil rights filmmaker Harvey Richards, portrays the interracial protests that took place in San Francisco in 1963-64.

Without the work of decomposers, living organisms would eventually use up all the raw materials in the environment, and dead organisms and wastes would pile up. This video segment from Interactive NOVA: "Earth" describes the role of decomposers as the earth's great recyclers.

In this video segment adapted from ZOOM, cast members use a hair dryer to balance a ball in a stream of air, seemingly defying gravity.

In this video segment, the ZOOM cast is challenged to keep a ping pong ball in a funnel while the funnel is held upside down, seemingly defying gravity.

Find out how controlled explosions are used to demolish multi-story buildings in this interview from the NOVA Web site.

In this video segment adapted from Navajo Technical College, meet a dendroclimatologist who studies the relationship between precipitation and tree growth in the Navajo Nation.

In this visualization adapted from the University of Massachusetts Medical School, discover the role that dengue viral proteins play in a human cell as the virus prepares to replicate.

Why does an egg float in salt water? Learn about density and buoyancy in this video segment adapted from ZOOM.

Watch warm water float on top of cold water in this video segment adapted from ZOOM.

This video segment adapted from ZOOM offers a clever demonstration of buoyancy by showing how to pour a cup of air into a cup filled with water.