Physical Science

Marijuana isn't just a recreational drug for hippies and philosophy majors -- its psychoactive history ranges from Egyptian mummies to modern U.S. politics. What's the big deal about this leafy, green plant?

By Kevin Bonsor & Nicholas Gerbis

You know how chocolate sometimes turns white? Why does that happen and is it still OK to eat?

By HowStuffWorks.com Contributors & Desiree Bowie

Without gasoline, the world as we know it would grind to a screeching halt. The U.S. alone consumes well over a hundred billion gallons of gasoline per year. Learn all about this vital fuel.

By Marshall Brain

You're driving down the road on a sunny day, and you see a puddle of water coming up. You look again and it's gone! What happened? You'll be able to answer that question if you read our miraculous mirage article.

By Tom Harris

Have you seen investigators on crime shows who spray some stuff on a "clean" carpet and suddenly -- blood stains! Well, of all the fictional technology on TV, it turns out this stuff is real! Find out how luminol reveals the blood.

By Tom Harris

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.

When you watch crime drama on TV, you don't usually see what happens after the police and ambulance leave a murder scene. One thing those people do not do is clean up the blood. That's the work of a whole different team.

By Julia Layton

The Diamond synchrotron is a massive facility that houses a beam of light 10 billion times brighter than the sun. But is that all it does?

By Jacob Silverman

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

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

Detectives arrive at a crime scene and lift fingerprints from the murder weapon. They'll use these oily markings to catch their criminal. But how do they match the print to the killer?

By Stephanie Watson

If you were to touch dry ice, it wouldn't be anything like touching water ice. So what's it like? Is it hot or cold? And would it leave a mark?

By Marshall Brain & Austin Henderson

We've all been told not to put aluminum foil in the microwave. Stories of incredible explosions and fires are usually at the center of these ominous warnings. Why is that?

By Marshall Brain

In detective movies or TV shows like "CSI," photographers swarm in and take countless pictures of a crime scene. But how does crime scene photography really go down?

By Sarah Dowdey

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

For centuries, curious observers have probed the heavens with the aid of telescopes. Today, both amateur and professional scopes magnify images in a variety of ways.

By Craig Freudenrich, Ph.D.