Gaussmeter, Earth's magnetic field, airfoil shape, and wing tip vortex may be meaningless terms for many people. They may not know that the Earth consists of a solid inner and a liquid outer core, which move around each other, creating the magnetic field that makes a compass needle point north. Probably no one except aviation engineers or those with a keen interest in the subject would know that fans—and the wings and propellers of aircraft—have an airfoil shape; and that the flow of air around them creates a lift that planes utilize during take-off and flight.