Physical Science

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

Topics to Explore

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How Telescopes Work

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.

Is it harmful to breathe 100-percent oxygen?

We need oxygen to live, so it seems to me that if we got more oxygen, we would be better off. Is it harmful to breathe 100-percent oxygen? What will happen?

How Nuclear Medicine Works

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

How Nuclear Power Works

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?

How Nuclear Radiation Works

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

How does rust work?

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.

How do one-way mirrors work?

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?

How Light Works

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.

Why does a mirror exchange left and right but not up and down?

Imagine wearing a T-shirt with lettering on it while brushing your teeth. Why are the letters on the T-shirt reversed in the mirror, while your head appears right side up?

Can two cans and a string really be used to talk over a distance?

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?

What makes glass transparent?

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?

What is dynamite and how does it work?

Dynamite is simply some sort of absorbent material (like sawdust) soaked in nitroglycerin. But what makes this chemical so explosive?

How do artificial flavors work?

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

If water is made up of hydrogen and oxygen, why can't we breathe underwater?

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.

What causes helium balloons to lose their lift after a day or two?

Scenario: A helium balloon is up against the ceiling one day, and the next day it's on the floor. Does the balloon fall because the helium leaks out, or because the helium molecules slow down due to decreased pressure?

How is helium made?

Helium is the second lightest element on the Periodic Table. How is helium created?

How does a lie detector (polygraph) work?

You may know a bit about polygraphs, but do you know which physical reactions it actually monitors? Get the scoop in this article.

What is a decibel, and how is it measured?

The decibel scale measures sound based on human hearing, which makes it one of the most unusual scientific measurements. How are decibel calculated and what do they tell us about sound?

How does chlorine bleach work?

I recently used chlorine bleach to clean the siding on my house, and I was amazed at how well it worked! What is bleach? How does it remove stains? Is the chlorine in bleach the same as the chlorine in drinking water or in swimming pools? Is chlorine safe to use?

Why is carbon monoxide poisonous?

I have heard that carbon monoxide is extremely poisonous. Can you explain why?

When I stand at the water's edge and look out over the ocean, how far away is the horizon?

When I stand at the water's edge and look out over the ocean, how far away is the horizon? Is there an equation to figure it out?

What is dioxin?

What is dioxin? There's a lot of discussion going on in my town about dioxin and its dangers.

How does a Crookes' radiometer work?

I once saw this device shaped like a light bulb. It had a vertical support inside it, and on that support there were four vanes with four diamonds on the end. One side of the diamond was black and the other was white. I did a little research and found out that it was called a Crookes' radiometer -- how does it work?

How does a Fresnel lens work?

I have a thin piece of plastic mounted on the back window of my RV. It magnifies things so I can see better when I'm backing up. How can such a thin piece of plastic magnify things? A regular glass magnifying lens would have to be curved on both sides and much thicker.


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