How 3-D Glasses Work

NASA’s Mars rovers are sending 3-D images to Earth, so we can see depth and texture on the Martian surface. And how do we see this depth and texture? 3-D glasses, of course! Check out how they work.

How Holograms Work

If you want to see a hologram, you don't have to look much farther than your wallet. But the most impressive holograms are large scale and illuminated with lasers or displayed in a darkened room with carefully directed lighting. Learn how a hologram, light and your brain work together make clear, 3-D images.

How Invisibility Cloaks Work

An “invisibility cloak” seems perfectly believable in the magical world of Harry Potter; but in the real world, it’s impossible, right? Not so fast. With optical-camouflage technology, the invisibility cloak is a reality.

How Lasers Work

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.

How Light Microscopes Work

The human eye misses a lot -- enter the incredible world of the microscopic! Explore how a light microscope works.

How Light Works

When we see an object, we are actually seeing light -- light that somehow left the object and reached our eyes. We also encounter light in things that produce it, from light bulbs, to lasers, to lightning bugs, to the sun. Learn how light waves are produced, how light travels, and how light explains the origin of color.

How Mirages Work

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? Learn what causes different kinds of mirages.

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.

Invisibility Cloak For Real This Time?

We first reported on the possibility of an invisibility cloak last year. Now a different invisibility cloak is making the news -- one that uses metamaterials to redirect light away from the wearer.

Is it possible to make a cloaking device?

A group of scientists from Duke University have demonstrated a simplified cloaking device. Learn about the cloaking device that the Duke scientists created and find out if a real-life cloaking device is actually possible.

Is there a light 10 billion times brighter than the sun?

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?

Does reading in low light hurt your eyes?

I read with a flashlight in bed all of the time. My grandma always says this is bad for my eyes and that I should get more light when I am reading. Will reading in low light hurt my eyes?

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?

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?

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.