Physical Science

Physical science is the study of the physical world around you. Learn about everything from electricity to magnetism in this section.

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Chemical formulas provide a concise explanation for reactions. In this article, we explain the formula for the reaction in a smoke detector.

When an airplane flies faster than the speed of sound, you hear a large booming sound. But how can something that seems so simple cause such a boom?

By Austin Henderson

Radar is used to track storms, planes, and weapons and also to create topographic maps. Learn about radar, radar technology and Doppler shift.

By Marshall Brain

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Nuclear materials get used in many forms of nuclear medicine -- everything from PET scans to chemotherapy uses them. Learn how nuclear medicine works.

By Craig Freudenrich, Ph.D.

On the one hand, nuclear power offers a clean energy alternative that decreases fossil fuel dependence. On the other, it summons images of quake-ruptured Japanese power plants leaking radioactive water. What happens in reactors in good times and bad?

By Marshall Brain, Robert Lamb & Patrick J. Kiger

The air we breathe contains 21 percent oxygen. Would we be better off breathing 100 percent oxygen?

By Marshall Brain

Alfred Nobel revolutionized several industries with his invention of dynamite. Learn more about how dynamite works and its controversial history.

By Yara Simón

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Just about everyone has seen a television show or movie in which a criminal suspect is questioned while detectives watch from behind a one-way mirror. How does a piece of glass manage to reflect light from one side while remaining clear on the other?

When there's a suspect in a crime and the evidence includes a handwritten note, investigators may call in handwriting experts to see if there's a match. How exactly do experts go about analyzing someone's handwriting?

By Julia Layton

The idea that something so intangible as acoustic levitation can lift objects may seem unbelievable, but it's a real phenomenon.

By Tracy V. Wilson

Magnets produce magnetic fields and attract metals like iron, nickel and cobalt. They're used in all sorts of applications but how are they made and how do they work?

By Tracy V. Wilson & Chris Pollette

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Rust is the common name for iron oxide, which is created when iron bonds with oxygen. In fact, pure iron is only rarely found in nature because it interacts with oxygen so easily.

I recently bought a pair of mirrored sunglasses and they are already scratched. Isn't there a way to make them scratch-resistant?

They stick around long after death and compete with the likes of Dracula, Frankenstein's monster and the Wolfman as one of the great figures of classic horror movies. Are you brave enough to unravel the history of these real-life, tangible ghosts?

By Tom Harris

The human eye misses a lot -- enter the incredible world of the microscopic! Explore how a light microscope works.

By Craig Freudenrich, Ph.D.

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Iran has announced its activation of a second set of uranium centrifuges. These machines are at the core of the uranium-enrichment process. Find out where the centrifuge fits into the equation.

By Marshall Brain

If you want to see a hologram, you don't have to look much farther than your wallet. But the most impressive holograms are large scale and illuminated with lasers or displayed in a darkened room with carefully directed lighting. Learn how a hologram, light and your brain work together make clear, 3-D images.

By Tracy V. Wilson

NASA's Mars rovers are sending 3-D images to Earth, so we can see depth and texture on the Martian surface. And how do we see this depth and texture? 3-D glasses, of course! Check out how they work.

By Marshall Brain

Most of us have heard the talk about oysters and chocolate, and maybe you've read an article about the stimulating effects of ginseng. But garlic, licorice and cucumber? Learn about the history of aphrodisiacs and whether they've been proven to be effective.

By Lee Ann Obringer

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An invisibility cloak seems perfectly believable in the magical world of Harry Potter, but in the real world, it's impossible, right? Not so fast.

By William Harris & Robert Lamb

Fusion reactors will use abundant sources of fuel, will not leak radiation above normal background levels, and will produce less radioactive waste than current fission reactors. Learn about this promising power source.

By Patrick J. Kiger & Craig C. Freudenrich

Learn what really goes on when a CSI "processes a crime scene" and get a real-world view of crime scene investigation from a primary scene responder with the Colorado Bureau of Investigation.

By Julia Layton

Electricity completely surrounds us whether you're charging your cell phone or watching the sky light up during a violent thunderstorm. For most of us, modern life would be impossible without it, and the natural world relies on it.

By Marshall Brain, William Harris & Robert Lamb

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The thought of an autopsy usually provokes fear, apprehension or extreme anxiety in people. Cut through the mystery of this process and learn the details of the preparation, procedures and tools used to perform an autopsy.

By Robert Valdes & Patrick J. Kiger

Viagra is one of the best-known drugs of all time. Nearly every adult in America has heard of the drug and can tell you what it does. Find out how this high-profile medication works its magic.

By Marshall Brain & Katie Lambert