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You need to push backward when you want to move forward. When you're walking down the street, your feet push back against the sidewalk to move you forward. In a car, the wheels do something similar by kicking back against the road. But what about the propellers that power airplanes?
A propeller is a machine that moves you forward through a fluid (a liquid or gas) when you turn it. It has several twisted blades poking out at angles from a central hub, spun around by an engine or motor. Propeller produces lift in a forward direction, a force we refer to as thrust. Its rotary motion through the air creates a difference in air pressure between the front and back surfaces of its blades. This pressure difference pushes the plane forward.
The simplest way to explain how a vacuum cleaner can suck up debris is to think of it like a straw. When you take a sip of drink through a straw, the action of sucking creates a negative air pressure inside the straw. A negative air pressure is lower than the pressure of the surrounding atmosphere.
A vacuum cleaner uses an electric motor that spins a fan and creates a region of low pressure inside its pipe, and the outside air pushes dust and dirt into the pipe.