Strawkets and Control
Figure 1. A controlled strawket.
Students investigate the effect that fins have on rocket flight. They construct two paper rockets that they launch themselves by blowing through a straw (see Figure 1). One "strawket" has wings and the other has fins. Students observe how these two control surfaces affect the flight of their strawkets. Students discover how difficult control of rocket flight can be and what factors can affect it. In the continuing hypothetical story for this unit, what students learn about rocket weight adds to their background understanding in their effort to help Tess launch a communication satellite.
Understanding how a rocket will behave in the Earth's atmosphere, as well as in space, is critical to rocket design. Engineers use control surfaces, such as fins, to help stabilize a rocket's launch into space. When designing other moving vehicles, engineers also need to consider the tradeoff of drag produced by adding control surfaces.
After this activity, students should be able to:
- Explain why the control of a rocket is important.
- Relate control of a rocket to fins and describe how fins affect rocket flight.
- Determine how the number of fins affects rocket flight.
- Identify some factors that engineers must consider when designing real rockets.