Ever wondered how that thing works? Explore the inner workings of many common devices and inventions, as well as those that aren't so common, such as compasses, gyroscopes and bug zappers.

How can I make my own battery to win a contest at school?

I am entering a chemistry contest at my high school. The goal is to build the battery that produces the most watts for one minute. Our battery can't be bigger then 1 foot in any direction and can't use strong acids. What are the best chemicals to use, and what's the best design?

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  • How CAT Scans Work

    How CAT Scans Work

    CAT scans take X-ray imaging to a whole new level. Find out how a CAT scan machine uses "slices" to form a 3-D computer model of a patient's insides. See more »

  • How Crossbows Work

    How Crossbows Work

    The crossbow, a weapon popular with Wookiees, vampire slayers and some modern hunters, looks like a cross between a bow and a rifle. Read about it’s fascinating history and uses. See more »

  • How does "bulletproof" glass work?

    How does "bulletproof" glass work?

    In a lot of movies you see windows that are "bulletproof." Does bulletproof glass really exist, and if so, how does it work? See more »

  • How does a Galileo thermometer work?

    How does a Galileo thermometer work?

    One of my co-workers has an interesting thermometer on his desk. It is a glass tube with different-colored floating things in it. What kind of thermometer is this, and how does it work? See more »

  • How does a rebreather work?

    How does a rebreather work?

    Unlike a regular SCUBA regulator which creates bubbles when the person wearing the apparatus exhales, a rebreather produces no bubbles when someone exhales. What exactly is a rebreather and how does it work? See more »

  • How Electromagnets Work

    How Electromagnets Work

    Whether they're sorting out scrap metal or helping us unlock the secrets of the universe, electromagnets are pretty nifty devices. What's so great about magnetism on demand? We'll electrify you with the details in this article. See more »

  • How fMRI Works

    How fMRI Works

    What if a scan could not only help diagnose diseases of the brain, but maybe even determine what we're thinking and feeling? A noninvasive fMRI test could do just that. See more »

  • How Gyroscopes Work

    How Gyroscopes Work

    Did you know that airplanes and space shuttles use the utterly low-tech gyroscope for navigation? Discover the secret behind gyroscopic motion! See more »

  • How LED Incapacitators Work

    How LED Incapacitators Work

    This nonlethal weapon doesn't cause any lasting damage, but it may cause you to pray to the porcelains gods if an officer shines one in your eyes long enough to subdue you. See more »

  • How Millimeter Wave Scanners Work

    How Millimeter Wave Scanners Work

    If you've traveled recently, you probably raised your arms above your head and waited for a millimeter wave scanner to do its screening thing. During those 10 seconds or so, did you ever wonder exactly how the device produced your image? See more »

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