Rocket ScienceBlast Off Experiment

Principles behind what makes rockets rock!

What You Need to Know ?• Aerospace engineering is the branch of engineering concerned with the

design, manufacture, and operation of launch vehicles, satellites, spacecraft, and ground-support facilities for the exploration of outer space. One type of spacecraft is a rocket, which is powered by gases that are forced out of one end.

• Rocket-like devices were demonstrated about 360 B.C. By the Greek mathematician and scientist Archytas (428-350 B.C.). So while some form of a rocket has been in existence for many years, the science of how a rocket works was first described by the British scientist Sir Isaac Newton (1642-1727) in 1687. Newton stated three important scientific principles that govern the motion of all objects, whether on Earth or in space.

• These principles, now called Newton's laws of motion, provided engineers with the basic knowledge necessary to design modern rockets such as the Saturn V rockets and the Space Shuttle Discovery.

We will check with this Simple Experiment

What You Need ?

• 6 feet (1.8 m) of string• 4-inch (10 cm) piece of drinking straw• 2 chairs• 9-inch (23 cm) round balloon• Spring clothespin• Transparent tape

What You Do:-1. Thread the string through the straw2. Tie the ends of the string to the backs of the chairs3. Position the chairs so that the string between

them is as tight as possible4. Inflate the balloon. Twist the open end of the

balloon and secure it with the clothespin5. Move the straw to one end of the string6. Tape the inflated balloon to the straw7. Remove the clothespin from the balloon

Thread the string through the straw

Tie the ends of the string to the backs of the chairsMove the straw to one end of the string

Inflate the balloon. Twist the open end of the balloon and secure it with the

clothespin

Remove the clothespin from the balloon

Clothes pin

Balloon

Straw

Tape

String Chair

Experiment Set-up

Animation of Blast Off

What Happened?

• The straw with the attached balloon quickly moves across the string. The movement stops at the end of the string or when the forces acting on the balloon are balanced.

Why?• When the inflated balloon is closed, the air inside pushes

equally in all directions. • The balloon doesn't move because all the forces are balanced. • When the balloon is open, the action-reaction pair of forces

opposite the balloon's opening is unbalanced.• One force is the walls of the balloon pushing on the gas inside

the balloon. This force pushes the gas out of the balloon's opening. The other force is the gas pushing on the balloon's wall opposite the opening.

• This force pushes the balloon in the direction opposite the opening.

THE END