Why Kitty Hawk, North Carolina?

[Forces] [Bernoulli's Principle] [Activities] [Books] [Wind Home]

For an airplane to fly, it must fight a battle between the forces of
thrust versus drag
and lift versus gravity.

THRUST -  the force that moves an airplane forward

 DEMONSTRATING THRUST

Everything needs thrust or force to make it go. If you leave a paper plane on the ground nothing will happen if the wind doesn't blow it. Try this experiment for yourself.

What Do I Need:

• string

• 2" section of straw

• tape

• 10" balloon

What Do I Do:

Slide section of straw through one end of string. Blow up balloon and carefully hold it closed with one hand. Have a friend tape the balloon to the straw. Holding the balloon at one end of the string with the opening of the balloon facing the closest end of the string. Have two friends hold the each end of the string. Let the balloon go and watch what happens.

DRAG - the force that pushes against an airplane and slows it down

 DRAG

Drag is the force that slows down things as they move through the air. On an airplane drag pushes against the plane and slowing it down. Try this experiment for yourself to find out how drag works.

What Do I Need:

• piece of poster board

• two friends

What Do I Do:

Find two friends who can run about as fast as each other. Have them stand next to each other on the start line. Give one friend a poster board to hold in front of him or her as they run. The other friend should run as usual. Record your observations.

LIFT - the force that pushes you up on an airplane and gives it the ability to climb into the air and stay up during flight

 LIFT

Lift is the force that pushes up on an airplane fighting the force of gravity. Swiss scientist, Daniel Bernoulli, did experiments that demonstrated when air flows over the surface of an object the force pushing down on the surface is reduced and the force pushing up on the surface becomes greater. Think of airplanes taking off and try this experiment for yourself to find out how lift works.

What Do I Need:

• piece of paper

• a friend

What Do I Do:

Cut a strip of paper about 2 inches wide by 11 inches long. Have a friend hold the strip up just under his or her lower lip. They should blow hard. Record your observations.

GRAVITY - the natural force of the earth that pulls down on an airplane

 GRAVITY

Gravity is the physical force that pulls objects together. It is the force that keeps us from floating off into space. The famous astronomer, Galileo, found that the speed at which bodies fall does not depend on their weight. Try this experiment for yourself to find out how gravity works.

What Do I Need:

• book

• pencil

• a friend

What Do I Do:

Have a friend hold the book in one hand and the pencil in the other. Make sure that are both the same distance from the floor. Drop both the book and the pencil at the same time. Record you observations.