Uplifting Elements

Type of Engineering involved: Chemical

Hydrogen and helium are the most common elements in the Universe. They are also the lightest. In fact, they are both lighter than air, so balloons filled with these gases will float.

At the beginning of this century, before commercial air travel took off, hydrogen was used to fill huge, passenger-carrying airships called dirigibles or zeppelins. Hydrogen is a very flammable, explosive gas, and, in 1937, a hydrogen-filled zeppelin from Germany called the Hindenberg exploded as it was landing in New Jersey. By that point, most other countries were filling their airships with helium which is an inert gas. Inert gases don't react with other chemicals and therefore don't burn or explode. Because the Nazi party was in power in Germany, scientists in the United States, who discovered how to manufacture helium, didn't share that technology with German scientists.

While using hydrogen for it's lighter than air properties is dangerous, engineers have found a great way to harness its explosive properties to get things into the air. Hydrogen is one of the two gases used to lift the Space Shuttle and other rockets into orbit around the earth - the other is oxygen. When hydrogen and oxygen are combined they both explode. On the Shuttle, all the energy from the explosion is channeled towards the ground and the force of the explosion actually pushes the spacecraft hard enough and fast enough to let it escape the Earth's gravity.