BrainStuff

Virtual first down lines are used to indicate where play resumes in football -- but how do they work? Listen in as Marshall Brain explains how the technology superimposes a virtual line in this podcast on HowStuffWorks.com.

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Dioxin is an organic chemical that consists of benzene, oxygen and chlorine. This chemical is also toxic. Tune in to learn more about dioxin and Agent Orange in this podcast from HowStuffWorks.com.

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If you look on the label of a water filter, you'll often see the filter contains activated charcoal -- but what exactly is this stuff? Tune in as Marshall Brain explains the nature of activated charcoal in this podcast from HowStuffWorks.com.

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SETI -- the Search for Extraterrestrial Intelligence -- is an enormous, global undertaking meant to detect signs of life beyond our solar system. Learn how you can help from home in this podcast from HowStuffWorks.

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Everyone's familiar with those little packets of silicate gel, found in thousands of products -- but what exactly do they do? Check out this HowStuffWorks podcast and learn more about silica gel.

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It's often said that "nature abhores a vacuum." If that's true, then why doesn't the vacuum of space suck away our atmosphere? Tune in as Marshall Brain explains the science behind vacuums in this HowStuffWorks podcast.

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If a balloon was filled by a vacuum -- rather than helium or air -- would it float? Check out this HowStuffWorks podcast to learn the science behind balloons and vacuum.

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An MRE -- or meal ready to eat -- contains precooked, sterilized food originally made to nourish soldiers. Check out this HowStuffWorks podcast to learn more about the retort packaging that makes MREs possible.

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Also known as 'lie detectors,' polygraphs are used to record an individual's vital signs, such as breathing rate, pulse, and so forth. Check out this podcast from HowStuffWorks to learn more about polygraphs and the art of lie detection.

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A Boeing 747 uses approximately one galloon of fuel per second -- over the course of a ten hour flight, it might burn 36,00 galloons of fuel. How does this compare to a car? Check out this HowStuffWorks podcast to learn more about airplane mileage.

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