It is used in surgery and dentistry for its anaesthetic and analgesic effects, where it is commonly known as laughing gas due to the euphoric effects of inhaling it. It is also used as a means to enable short periods of extreme high performance in automobile internal combustion engines by introducing extra oxygen into the intake charge which in turn allows a greater amount of fuel to be added and converted into energy and thereby greatly increasing the power produced by the engine. Nitrous oxide is present in the atmosphere where it acts as a powerful greenhouse gas.
The reason firehouses have circular stairways is from the days of yore when the engines were pulled by horses. The horses were stabled on the ground floor and figured out how to walk up straight staircases.
The lowly krill averages only about two inches (5 centimeters) in length, but it represents a giant-sized link in the global food chain. These small, shrimp-like crustaceans are essentially the fuel that runs the engine of the Earth’s marine ecosystems.
When a circuit breaker switch broke on the lunar module, Buzz Aldrin used a felt-tip pen to push it in so the engine could fire and lift them off the Moon.
George and Robert Stephenson's locomotive Rocket won the 1829 Rainhill Trials, a competition to find the best engine for the new Liverpool and Manchester Railway.
When no company could build a light enough engine, the Wright brothers' mechanic Charlie Taylor built a 12-horsepower engine for the Wright Flyer in just six weeks.
Hero of Alexandria described the aeolipile, a spinning steam-powered device, in the first century AD, but it was treated as a curiosity rather than a machine for work.