Physical Science

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

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?

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.

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

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

The bloodstain from a crime scene has a story to tell, if you know how to analyze it. Then it might explain the who, what and when of a murder.

By Shanna Freeman & Melanie Radzicki McManus

Mass spectrometry enables the major league to sniff out athletes guilty of doping. It can also help us locate oil or design a killer perfume. Who says chemistry isn't cool?

By William Harris

First, you burn the body until only brittle, pulverized bones are left. These remains are pulverized into ashes, and then placed into urns -- or diamonds, coral reefs and even outer space.

By Michelle Kim

Overtone is a sound accompanying the main tone produced by a vibrating body. The number and loudness of overtones determine the timbre, or tone color, of a musical sound.

An object free to vibrate tends to do so at a specific rate called the object's natural, or resonant, frequency.

When sound waves strike the ear, these waves produce the sensation of sound. Let's take a look at how sound waves work.

Once considered a semiprecious metal alongside gold and silver, aluminum pretty much languished in obscurity until the 19th century. How did the metal become so ubiquitous?

By William Harris

Imagine spending your days racked with pain or losing pound upon pound because nausea leaves you unable to eat. Now imagine that someone offers you a wonder drug to cure all your ills. The problem? It's illegal.

By Jacob Silverman

If you were thrown into prison for a crime you didn't commit, you'd probably welcome DNA profiling. Although the use of this technology has recently helped bring justice, there may be cause for concern.

By Shanna Freeman

A venerable work of art hangs lifeless in a museum, the once brilliant scene dulled by centuries of dirt and grime. Can laser analysis and modern art restoration techniques save the masterpiece?

By William Harris

Can you pass the acid test? That electric Kool-Aid changed the fabric of 1960's American counterculture. So, what's it's like to trip on LSD?

By Shanna Freeman & Nathan Chandler

We love it. We wear it glittering around our necks and sparkling at our ears, wrists and feet. We pass it down to our children and hoard it in secret stashes. Why is this precious metal so prized?

By William Harris

Mushrooms – they're not just a pizza topping. This psychotropic fungus has guided many an adventurer on a trip. How do shrooms make their magic?

By Shanna Freeman & Nathan Chandler

We once emptied the scent pods of male musk deer into a bottle of fragrance and doused it on, feeling like a million bucks. How has perfume changed since then?

By Susan L. Nasr