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.
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.
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.
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.
An MRE -- or meal ready to eat -- contains precooked, sterilized food originally made to nourish soldiers.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.
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.
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.
CDs store music using 44,100 16-bit digital samples per second, adding up to about 10 megabytes per minute -- and that's too large to move easily move across the internet. Check out this HowStuffWorks podcast to learn how MP3 files solve this problem.
All cells contains thousands of enzymes, and each of these enzymes is necessary for the cell. Check out this HowStuffWorks podcast to learn which enzymes cause apples and potatoes to turn brown upon exposure to oxygen.
In houses with a built-in sprinkler system, anti-siphon valves prevent pesticides, pet waste, and other contaminants from polluting the home's water source. Check out this HowStuffWorks podcast to learn more about anti-siphon valves.
A normal 120 volt outlet in the US has two vertical slots and a role hole centered below the slots -- the outlets with a pair of red and black 'test' and 'reset' buttons are known as GCFI outlets. Check out this HowStuffWorks podcast to learn more.
By using a computer to monitor the rotation of the car's wheels, an anti-lock braking system helps drivers avoid skids. Could this computer also monitor flat tires? Check out this HowStuffWorks podcast to learn more about brake systems.
The sound of gunfire is incredibly loud, and it is amazing that anything is able to silence a firearm. However, the principle behind a gun silencer is surprisingly simple. Check out our HowStuffWorks article to learn more about silencers.
Since the heart is a muscle, it relies on the oxygen and nutrients contained in blood. This blood is supplied by arteries on the exterior of the heart -- when these arteries are blocked, a heart attack results. Take a look at our HowStuffWorks article to
There are three different technologies that fall into the catapult category: the ballista, the trebuchet and the catapult. Check out this HowStuffWorks podcast to learn more about the differences between catapult technologies.