This video segment from Evolution: "Darwin's Dangerous Idea" illustrates the remarkable camouflage of a praying mantis against its leafy backdrop.

This video from Evolution explores the evolution of humans from a common ancestor of humans, chimpanzees, and other apes.

This video from Evolution highlights Charles Darwin's personal struggle to bring to light his theory of evolution through natural selection.

In this video from Evolution, an exploration of multi-drug resistant tuberculosis in the Russian prison system highlights one reason it is important to understand evolution.

In this video segment adapted from NASA, students in Matsuyama City, Japan, interview Expedition 8 Commander and NASA Science Officer Mike Foale and Flight Engineer Alexander Kaleri about life and work aboard the International Space Station.

In this video segment adapted from ZOOM, the cast investigates how the pitch of sound changes when they strike a variety of glasses filled with different amounts and types of liquids.

Can a fresh lemon power a digital clock? In this video segment adapted from ZOOM, the cast shows you how this can be done and, in the process, discover how kids can be a part of an electric circuit.

See what it is like to walk on the Moon by viewing this collection of QuickTime images from NOVA Online. Stunning 360-degree panoramas from each of the six successful Apollo Moon landings are featured.

In this video segment from Religion & Ethics Newsweekly, learn about Muslims in Lawrenceville, Georgia, their plans to build an Islamic cemetery and the stiff objections from their Christian neighbors.

Join Tarissa and Sabrina as they measure and compare the volume of different sounds across New York City in this video from DragonflyTV.

In this video segment adapted from Interactive NOVA, astronaut John Young experiences extreme temperatures on the Moon that are a result of the Moon's low gravity and lack of atmosphere.

The CyberSquad tests which broom can travel the furthest in five seconds in this video from Cyberchase.

In this video segment adapted from NOVA scienceNOW, scientists in western Greenland explain how a glacier there is shrinking and moving faster due to increased melting.

The CyberSquad solves the problem of giving equal parts of two apples to Cerberus, the three headed dog of Greek mythology, in this video from Cyberchase.

In this video from Nature, watch how ravensŰ__Ű__ŒŒÇ smarts can be observed in many situations, such as when they hunt and store food.

This video describes the role of the brain in regulating body temperature and how sometimes fever is employed to fight off infection.

This video segment from the teacher video series Learning That Works uses a case study to highlight the effectiveness of a project-based, real-world approach to teaching science.

In this video segment from Cyberchase, through addition and regrouping in base sixty, Matt helps Digit figure out what time his CyberSoufflŰ__ŒŰÖ will be done.

The CyberSquad reviews their budget for the second day of their film shoot in this video from Cyberchase.

In this video segment from Cyberchase, the CyberSquad compares their budget with their actual spending from day three of their film shoot.