The peacock provides a classic example of sexual selection, the force behind nature's extravagances. From Evolution: "Why Sex?"

Bonnie Chen builds on students' prior knowledge of mutations to lead her class through a simulation of wading birds feeding.

Marilyn Havlik leads students through a simulation of the Hardy-Weinberg Principle to develop their understanding of population genetics.

This is a workshop on Skimming, Scanning, and Interpreting | Teaching Foreign Languages K-12 Workshop.

In this video adapted from KUAC-TV and the Geophysical Institute at the University of Alaska, Fairbanks, learn how tectonic plate movement is responsible for building mountains, such as the Wrangell and St. Elias Mountains.

This interactive activity produced for Teachers' Domain shows the relationship between tectonic boundaries and the locations of earthquake events and volcanoes around the world.

In this transcript of an interview filmed for Evolution: "Great Transformations," Ted Daeschler and Neil Shubin describe the discovery and significance of some of their key fossil finds.

In this video adapted from Earth Island Institute, meet a high school student who educated her community about how a coal-burning power plant was contributing to asthma and other health problems there.

Why do teenagers act the way they do? This video segment from FRONTLINE: Inside the Teenage Brain explores the work scientists are doing to explain some of the mysteries of teenage behavior.

In this video adapted from Earth Island Institute's New Leaders Initiative, meet a high school student who worked to enact a state law to make cosmetics safer, after she learned they contained toxic chemicals linked to cancer.

Watch the ZOOM cast discover which insulator -- newspaper or aluminum foil -- is better at keeping an ice cube frozen longer.

In this video segment adapted from ZOOM, cast members show you how to make your very own electroscope. You can use it to find out if an object is electrically charged.

In this video segment from Cyberchase, learn about the importance of creating a model as the CyberSquad designs a giant Trojan Ducky that will help them enter a fort without being noticed.

This illustration from Evolution by Monroe W. Strickberger shows the remarkable similarities between the bones in the forelimbs of various tetrapods, all of whose limbs serve very different functions.

This interactive activity from the NOVA Web site challenges you to think like Einstein and understand how time travel might be possible.

Examine how the human/grizzly relationship has changed since the closing of the Yellowstone dumps, and also learn about the challenges posed to both humans and bears, in this video segment from Nature.

This video from NASA explains the process by which gamma-ray flashes associated with storms produce matter/antimatter particle pairs.

This illustrated essay from the NOVA Web site answers questions about irregularities in the tides.

In this lesson designed to enhance literacy skills, students learn that transitional fossils provide scientists with evidence to establish how major animal groups are related to one another.