# Topic – Taking Flight

Read about taking flight, or click on the play button below to listen aloud.

### Taking Flight

Find out about the four forces of flight: lift, weight, drag, and thrust.

### Just a Little Lift

Lift helps an airplane overcome its weight. Lift also helps the plane rise into the air, and stay up in the air. Many parts of a plane work together to create lift. Most lift is generated by the wings.

Look at a bird’s wing when it is flying. You will see that it curves so that the top side is longer than the bottom.
Planes create lift in the same way.

Air moving over the curved wing top goes farther than air going under the wing. The air also moves faster. Air that is moving more quickly exerts less pressure. So the air below the wing pushes up harder than the air above the wing pushes down. That lifts the plane into the air.

### What a Drag!

When a plane moves through the air, the plane has to overcome drag. Drag is a force similar to friction. Drag slows down objects moving through air. Every part of a plane generates drag, even the engines.

The more streamlined, or aerodynamic, the plane is, the less drag the plane creates. The less drag the plane creates, the faster and more easily the plane can move through the air.

### Overcoming Gravity

Earth’s gravitational force makes it difficult for a plane to fly. You measure the force of gravity (weight) whenever you step on a scale. Gravity is a force that keeps a plane on the ground.
The weight of a plane has to be overcome before it can fly.

### Give It Some Power

Thrust is the force that propels an aircraft through the air. Thrust is used to overcome the plane’s weight and the drag of the air on the plane.

Birds create thrust by flapping their wings. In an aircraft, thrust is generated by the engines. Thrust makes lift possible.

### Now, show what you know!

Complete some questions about the reading selection by clicking “Begin Questions” below.