Physical Science

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 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

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

By Patrick J. Kiger

Metallurgy involves studying how metals behave and using that understanding to manipulate and shape them into various forms.

By Desiree Bowie

If you're already familiar with subtracting fractions, learning how to add fractions will be a piece of cake for you. And if you haven't learned how to subtract fractions yet, don't worry - we've got you covered!

By Jesslyn Shields

How effective is fighting a wildfire with controlled fire?

By Oisin Curran

In 1957, Hugh Everett first wrote about the multiverse - different realms where every choice spawns a separate universe in which another version of ourselves does something different. It sounds crazy, but here are some reasons it might be true.

By Patrick J. Kiger

Magnetism is at work all around you. Even our Earth is a giant magnet!

By Jesslyn Shields

An imaginary number is a value that's the square root of a negative number. It can't exist on a one-dimensional number line. We'll explain.

By Patrick J. Kiger & Austin Henderson

First discovered in the late 1930s, muons are passing through you and everything around you at a speed close to light, as cosmic rays strike particles in our planet's atmosphere. So what are muons and how are they informing the new physics?

By Patrick J. Kiger

The lava-like material that formed after the Chernobyl nuclear disaster is a deadly example of corium, a hazardous material created only after core meltdowns. Five minutes next to it can kill a human.

By Patrick J. Kiger

Numerators and denominators, oh my! It sounds complicated, but learning how to multiply fractions is easy. It just takes three simple steps.

By Jesslyn Shields

Dividing fractions is easy once you learn a couple of rules and remember three words - keep, change and flip.

By Jesslyn Shields

A perfect square is a number, but it can also be explained using an actual square.

By Jesslyn Shields & Austin Henderson

Real numbers are the opposite of imaginary numbers and include every number you can think of.

By Jesslyn Shields & Yara Simón

If you have trouble sleeping you might have been told to get a white noise machine. But white isn't the only color of noise out there.

By Talon Homer & Austin Henderson

We'll show you both a quick and dirty way, and a precise, more complicated formula for converting Celsius to Fahrenheit (and vice versa).

By Sydney Murphy & Austin Henderson

Discovered in the early 1800s from a chunk of smuggled platinum ore, rhodium is the most valuable precious metal on the planet today, used mainly for keeping car emissions in check.

By Allison Troutner & Austin Henderson

The main function of the Krebs cycle is to produce energy, stored and transported as ATP or GTP, to keep the human body up and running.

By Jesslyn Shields & Austin Henderson

Many people get speed and velocity confused. It's no surprise because the terms are often used interchangeably. But they're not quite the same thing. So how do you find the velocity of an object?

By Mark Mancini