Will a grape float in oil? Will a metal nut sink in corn syrup? Watch as the ZOOM cast tests the buoyancy of a variety of liquids and objects.

This video segment from NOVA: A Desert Place describes the physical characteristics and organisms that define the desert biome.

In this video segment adapted from Design Squadí_í_íŹa PBS TV series featuring high school contestants tackling engineering challengesí_í_íŹlearn about the fundamentals of sound as student teams create percussive and stringed instruments for a local band.

In this video segment adapted from Design Squadí_í_íŹa PBS TV series featuring high school contestants tackling engineering challengesí_í_íŹstudents employ the concepts of tension and compression to build a suspension bridge without the aid of power tools.

In this video segment adapted from Design Squadí_í_íŹa PBS TV series featuring high school contestants tackling engineering challengesí_í_íŹstudents employ the concepts of tension and compression as they build a truss bridge without the aid of power tools.

In this video segment adapted from ZOOM, cast members design and build door alarms using a variety of materials, including aluminum foil, batteries, and buzzers.

In this video segment adapted from ZOOM, cast members discover that metal is a good conductor of electricity as they play the steadiness tester game.

In this video segment adapted from ZOOM, cast members make a bridge from a single piece of paper. Will it be strong enough to hold a hundred pennies?

In this video from NOVA scienceNOW, learn how scientists detect potential signs of life on distant planets.

This video segment from Greater Boston examines whether environmental toxins may be to blame for a rare skin disease.

Our understanding about the air we breathe has changed dramatically through time. This illustrated timeline from the NOVA Web site tracks the changing thought on air and the creation of the Periodic Table of the Elements.

This video segment adapted from A Science Odyssey tells the story of researcher Sir Alexander Fleming, whose luck and scientific reasoning led to the groundbreaking discovery of penicillin.

In this interactive activity from the Building Big Web site, think like an engineer and use your knowledge of dome design to match the right type of dome to the right location in a fictitious city.

Dr. Stephen O'Brien of the National Cancer Institute discovers a 700-year-old mutation that makes a person resistant to HIV infection. From Evolution: "Evolutionary Arms Race."

In this transcript from FRONTLINE: "Inside the Teenage Brain," neuroscientist Dr. Jay Giedd discusses new research on brain development in teenagers.

In this video adapted from ANDRILL, find out how geoscientists get through more than a dozen football fields of ice and water in order to study the rock and sediment beneath Antarctica.

This video segment from NOVA: "The Shape of Things" follows the growth of a duck embryo, from a single fertilized egg cell to a complex, hatching duckling.

In this video profile produced for Teachers' Domain, meet teacher Dustin Madden, an IŰ__ŒóíŠupiaq who hopes to inspire students to take an active role in protecting the natural environment by giving them a foundation in math and science.

This video segment adapted from NASA's Goddard Space Flight Center discusses how a drought can have negative effects locally, for example by increasing the number of forest fires, and also globally, for example by impacting air quality thousands of miles away.

This video segment adapted from NASA's Goddard Space Flight Center describes El NiŰ__ŒóíŠo, how it forms, and the chain reaction of consequences it triggers around the globe.