Joe Palca

Sometimes the true value of an invention isn't obvious until people start using it.

Consider what happened to inventor Nate Ball and his powered ascender. About 15 years ago, Ball was an undergraduate at the Massachusetts Institute of Technology when the U.S. Army approached MIT with a request: Can somebody build a powered device that can pull somebody up a rope, like Batman does?

There is a lifesaving drug that owes its existence to moldy hay, sick cows and rat poison.

When you want to change the world, a good invention helps. But that is just the start.

Take the story of Mike Davidson and Mike Smith: They wanted to change the world of dental hygiene with a new kind of toothbrush.

Three years ago, their brushes were rolling off the assembly line, ready for consumers. But then the pair ran into a business buzz saw, and it changed the way they saw the business of invention forever.

A prototype of what could be the next generation of space stations is currently in orbit around the Earth.

The prototype is unusual. Instead of arriving in space fully assembled, it was folded up and then expanded to its full size once in orbit.

Even the most commonplace devices in our world had to be invented by someone.

Take the windshield wiper. It may seem hard to imagine a world without windshield wipers, but there was one, and Mary Anderson lived in that world.

In 1902, Anderson was visiting New York City.