Blast Off: Generating Rocket Thrust with Propellants
Ancient Chinese fire-arrows.Copyright NASA Quest http://quest.arc.nasa.gov/ space/teachers/rockets/ history.html
Rockets need a lot of thrust to get into space. Students learn how rocket thrust is generated with propellant. The two types of propellants are discussed—liquid and solid—and their relation to their use on rockets is investigated. Students learn why engineers need to know the different properties of propellants by drawing real world examples from the associated activities.
Engineers use powerful propellants to launch rockets into space. When these propellants burn, hot gas is expelled out the nozzle causing the rocket to move forward. To achieve the necessary speeds, engineers must understand the chemical properties of the different propellants. Factors such as weight, efficiency, controllability and safety must be kept in mind when choosing a propellant. Specific propellants are better for different tasks, and it is the job of engineers to choose which and how much of a propellant to use.
After this lesson, students should be able to:
- Apply Newton's third law of motion to explain how a rocket launches.
- Explain the difference between propellant and fuel.
- Describe how fuel weight affects the ability to get a rocket into space.
- Explain why engineers need to know the properties of different propellants.