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 the elements will float.

Before airplanes, hydrogen was used to fill huge airships called dirigibles or zeppelins. Hydrogen is a very  explosive gas that easily catches fire, 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.

Since hydrogen can be dangerous, engineers now use it to get things into the air. Hydrogen is one of the two gases used to rockets into space - the other is oxygen. When hydrogen and oxygen are combined they both explode. On space shuttles, all the energy from the explosion is pushed towards the ground and the force of the explosion pushes the shuttle hard enough and fast enough to let it escape the Earth's gravity!