A man sits down before a gun, which is pointed at his head. This is no ordinary gun; i­t's rigged to a machine that measures the spin of a quantum particle. Each time the trigger is pulled, the spin of the quantum particle -- or quark -- is measured. Depending on the measurement, the gun will either fire, or it won't. If the quantum particle is measured as spinning in a clockwise motion, the gun will fire. If the quark is spinning counterclockwise, the gun won't go off. There'll only be a click.

Perhaps you've visited a restaurant and seen clear, water-filled bags hanging on the doors or cinched up in the outdoor dining area. You might ask, "What's all this about? Some crazy new way to control temperature? A scheme to save money on water pitchers?"

Some inventions are designed to save people's lives. Some improve the way we live, while others make things easier or more convenient for us. And some inventions cause revolutions that forever change the course of human history -- light bulbs, automobiles and space travel are examples of this.

It may be hard to imagine, but just a mere 20 years ago, the Internet was nothing more than a novelty -- a way for incredibly smart college professors and researchers to share information, and for a few people to network across the newly developed World Wide Web. E-mail was nothing like it is today. The primitive e-mail systems found at universities or even through accounts offered with the first Internet service providers (ISPs) such as Prodigy and America Online were often difficult to use.

Just a pinch of it and it’s worth it. We’re talking salt here. Used throughout human history, mentioned often in the Bible, ubiquitous and cheap. Mined from salt rocks and extracted from sea water, salt is… well, the “salt of the earth.” You can’t live without it healthily. At the same time, you can’t live healthily with too much of it. Get the balance right – in your food and in your live – and salt is worth it’s own weight.

Reichelt announced to the press in early February 1912 that he had finally received permission to conduct an experiment from the Eiffel Tower to prove the value of his invention, the “parachute suit”.

It never hurts to be careful in this crazy world we live in. In daylight hours, refresh yourself of these 10 crucial safety tips that will help you in an emergency situation. The tips were written by personal safety adviser Pat Malone and have been shared via email by millions of people. It is worth repeating:

In 1958, President Eise­n­hower signed the Space Act, officially creating the National Aeronautics and Space Administration. From the beginning, the purpose for the ne­w branch extended beyond space ships and moon boots. The law stipulated that its research and advancements should benefit all people, and in its 50-year history, NASA has certainly fulfilled that role.