This video segment describes the basics of the circulatory system: how the heart pumps the blood that carries oxygen and nutrients throughout the body.

This video from NASA describes the GLAST satellite, which is equipped with a gamma-ray telescope, and shares some background about the kinds of extreme universal phenomena indicated by the presence of gamma rays.

In this animation produced by WGBH and Digizyme, Inc., see how bacterial plasmids are engineered to clone or express genes that code for proteins such as human insulin.

In this video profile adapted from NOVA scienceNOW, learn about geneticist and rock musician Pardis Sabeti, whose innovative insights into natural selection demonstrated how beneficial mutations spread quickly through a population.

Kibera, a poor community, in Nairobi, was a blank spot on the map until recently. This video from Penn State Public Broadcasting’s Geospatial Revolution shows how geospatial technology enabled residents to map resources to help their community.

This video segment, adapted from NOVA, chronicles the education of leading chemist Percy Julian. Although Julian began his elementary school years in the Deep South under Jim Crow laws, he became one of the few African Americans of his time to earn a Ph.D.

This video segment adapted from NOVA/FRONTLINE examines the greenhouse effect, its role in keeping Earth habitable, and the industrial changes that have led to an increase in the planet's average temperature.

In this lesson designed to enhance literacy skills, students learn how to read and interpret a distance–time graph.

Students are introduced to graphing on the coordinate plane, in the first quadrant, using (x, y) coordinates.

In this video segment adapted from NOVA, watch residents of the Peruvian Andes build a suspension bridge made entirely of grass. The ancient Inca were a textile society and thus skilled in working with natural fibers including alpaca and cotton. Still, it might surprise people today that their solution to crossing the canyons and gorges of their mountainous empire featured another fibrous material: grass. When you consider how they built a simple suspension bridge, you'll realize that not only was this a practical solution, it was also a safe one. In this video segment adapted from NOVA, watch residents of the Peruvian Andes as they build a traditional and functioning grass bridge the likes of which enabled the ancient Inca people to flourish for several hundred years. Grades 3-12.

Learn about a study in which participants discovered contaminants in their homes, and how green chemistry may provide alternatives to such everyday toxins, in this video adapted from Contaminated Without Consent.

In this video segment from Cyberchase, the CyberSquad determines the fairness of a game in which there are three shapes distributed equally on nine squares. ***Access to Teacher's Domain content now requires free login to PBS Learning Media.

Harry keeps track of the number of times he sneezes in certain locations to try to diagnose the cause of his allergy in this video segment from Cyberchase.

In this video segment adapted from United Tribes Technical College, meet Native Americans who are concerned about climate change and believe that action today can help future generations once again live in harmony with Earth.

Aaron and Justin investigate which sunscreen best keeps out harmful ultraviolet rays from the Sun, in this video from DragonflyTV.

In this video segment adapted from Shedding Light on Science, observe demonstrations of the fundamental idea that light travels in straight lines.

In this video segment adapted from NOVA, explore the theory that small bits of gas and dust combined to form protoplanets billions of years ago, which in turn collided to create the four rocky planets of the inner solar system.

Students learn how the human body self-regulates to maintain a stable internal environment despite changes in the external environment.

Students investigate hominid evolution. They learn the difference between a relative and an ancestor, study the emergence of bipedalism, and chart patterns of hominid migration.

This video segment from The Human Spark features a discussion about how human thought differs from that of chimpanzees.