Physical Science

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?

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

By Patrick J. Kiger

You may know a bit about polygraphs, but do you know which physical reactions it actually monitors?

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?

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?

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? Is there an equation to figure it out?

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

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?

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.

Bullets, wires and nails are all measured with unusual measurement systems and units -- and they all show just how interesting measurement systems can be!

Many ads for new clocks advertise their ability to automatically synchronize themselves with the atomic clock in Boulder, Colorado. This atomic clock is more precise because it uses the frequencies of atoms as its resonator.

Chemical formulas provide a concise explanation for reactions. In this article, we explain the formula for the reaction in a smoke detector.

Radar seems to have infinite uses: Police use it to clock your speed, NASA uses it to follow satellites, meteorologists use it to track storms and the military uses it to track the enemy ... Learn all about radar technology!

By Marshall Brain

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

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

Lasers are used in CD players, dental drills, eye surgery, and even tattoo removal. But what exactly is a laser? There are numerous types, but all lasers work basically the same way. Learn how they generate such concentrated beams of light.

By Matthew Weschler