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This page provides an explanation of how airplanes fly in simple terms, and is meant as a brief introduction to the topic. No attempt will be made to discuss all of the real-life factors involved in flight or the mathematical formulas needed to compute the results of these factors on an airplane in flight.

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Defining Gravity: Crash Course Kids #4.1

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Four Forces Affect Things That Fly:

1. Weight is the force of gravity. It acts in a downward direction-toward the center of the Earth.

2. Lift is the force that acts at a right angle to the direction of motion through the air. Lift is created by differences in air pressure.

3. Thrust is the force that propels a flying machine in the direction of motion. Engines produce thrust.

4. Drag is the force that acts opposite to the direction of motion. Drag is caused by friction and differences in air pressure.

All Four Forces Act on an Airplane

When an airplane is flying straight and level at a constant speed, the lift it produces balances its weight, and the thrust it produces balances its drag. However, this balance of forces changes as the airplane rises and descends, as it speeds up and slows down, and as it turns.

Only Two Forces Affect a Spacecraft in Space

A spacecraft has weight, even in orbit, and uses thrust to reach space and to maneuver. But lift and drag-both created by movement through air-are absent in the near vacuum of space.

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Four Forces Affect Things That Fly: Weight is the force of gravity. It acts in a downward direction-toward the center of the Earth. Lift is the force that acts at a right angle to the direction of motion through the air.

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The Four Forces Of Flight - NASA SCI Files

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Audience: Grade Level 3-5 Producer: NASA LaRC Office of Education Click to subscribe! http://bit.ly/subAIRBOYD The most viewed aviation channel on YouTube.

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Drag (physics) Facts for Kids | KidzSearch.com

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In aerodynamics, drag (sometimes called resistance) is a force which tends to slow the movement of an object through a liquid or gas. As a moving object pushes the liquid or gas out of its way, the fluid pushes back on the object.