See also momentum below.
Convection is the movement of heat within a gas or liquid by the circulation of currents.
Convection cell describes the cyclical pattern of movement of a gas or liquid such as the atmosphere, the ocean, or the Earth's mantle. The term jet stream was coined by the first pilots who encountered this strong wind, to whom it seemed as though the air was being blown out of a gigantic nozzle, or jet. The force or energy associated with an object in motion. Also known as linear momentum. If an object's linear momentum has no external force acting on it, then that object's momentum will not change.