Physical Science

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

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

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

Crack cocaine, like many other illegal drugs, leads to addiction, death, increased crime rates and imprisonment. But this drug targets the inner city almost exclusively and possession or distribution of crack carries extremely harsh prison sentences.

By Stephanie Watson & Nathan Chandler

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

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 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

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

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.

More than 2.3 billion people across the globe drink alcohol, but most don't consider it a drug. But if you've ever seen someone who's had too much, you know alcohol has profound effects on the mind and body.

By Craig Freudenrich, Ph.D. & Michelle Konstantinovsky

Smoking or chewing tobacco makes many people feel good, even mildly euphoric. It's the nicotine that produces the buzz. Find out how nicotine affects the human body and what makes it so addictive.

By Maria Trimarchi & Ann Meeker-O'Connell

Do you remember holding a large conch shell up to your ear to hear the ocean? Why does this work even when you're far away from the sea?

What exactly is an atom? What is it made of? What does it look like? The pursuit of the structure of the atom has married many areas of chemistry and physics in perhaps one of the greatest contributions of modern science!

By Craig Freudenrich, Ph.D.

Biting on aluminum foil can be painful -- basically, when you bite on foil, you build a battery in your mouth. Ouch!

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.

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