Physical Science

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

It begins with an unassuming "H" and ends in crazy elements that you've likely never heard of. But the periodic table, encapsulated on a mere sheet of paper, can be a scientist's best friend and a testament to our human drive to organize the world.

By Craig Freudenrich, Ph.D.

When it comes to stimulating the human central nervous system, meth can hold its shaky, toothless head high. Why is this drug so additive?

By Tom Scheve & Nathan Chandler

If the sight of a mushroom cloud burning above the horizon suggests that the nuclear weapon-equipped world might end with a bang, then nuclear winter presents the notion that post-World War III humanity might very well die with a whimper.

By Robert Lamb

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

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

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

If serial killer Ted Bundy hadn't been a biter, he might never have been caught. What can bite marks and teeth tell us about a person?

By Shanna Freeman & Melanie Radzicki McManus

Forensic scientists can help law enforcement catch even the wiliest perpetrator. What are their techniques?

By Stephanie Watson

Will your favorite criminal drama feature investigators packing calculators instead of heat? Probably not. However, forensic accountants help investigate criminal and civil cases involving financial issues like fraud.

By Shanna Freeman

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

Here's something to consider: The place you call home likely has walls and glass windows. Both are adept at keeping rain, snow and wind from bothering you in your abode. Only one, though, allows light to enter. Why is that?

By William Harris

Atom smashers tell us about the fundamental structure of matter, the forces holding it together and the origins of the universe. Discover how scientists use particle accelerators to break atoms apart to learn about the nature of reality.

By Craig Freudenrich, Ph.D.

I was watching an old movie today, and two kids (neighbors) were talking to each other using two tin cans and a string. Does that really work? If so, why does it work?

Some of the brightest minds in history have focused their intellects on the subject of light. Einstein even tried to imagine riding on a beam of light. We won't get that crazy, but we will shine a light on everything scientists have found so far.

By William Harris & Craig Freudenrich, Ph.D.

If water is made up of hydrogen and oxygen, why can't we breathe underwater? It has to do with how molecules combine and how the human lung functions.

Ever wondered exactly what they "artificial flavors" in your candy are, and why no specific ingredients are listed? Find out in this article.

By HowStuffWorks.com Contributors & Yara Simón

If the idea of being completely knocked out by a cocktail of drugs while doctors operate on you freaks you out, you're not the only one. But that's not what anesthesia is all about it — and it might scare you less if you understand how it works.

By Shanna Freeman & Nicole Antonio

When the power goes out and is later restored, how do you know what time to set your clocks to? Have you ever wondered how time is regulated? Learn how scientists determine exact time.

By Douglas Dwyer

About 90 percent of Americans consume some form of caffeine every day: It's our most popular drug by far. What's so special about this stimulant?

By Marshall Brain, Charles W. Bryant & Matt Cunningham

Helium balloons tend to fascinate adults and children alike (and it's not just the Donald Duck voice thing, though that is a big draw). Learn all about helium and why it floats!

By Marshall Brain

Nuclear radiation can be extremely beneficial or extremely harmful -- it all depends on how it's used. Learn what nuclear radiation is all about.

By Marshall Brain & Desiree Bowie

Whether the circle is as big as planet Mars or as small as a tennis ball, the ratio of its circumference divided by its diameter will always equal pi (3.14). But why?

By Marshall Brain, Dave Roos & Austin Henderson

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