Learning Objective:
By constructing and testing a slingshot rocket, each student will comprehend basic aerodynamic principles such as stability, drag, and lift. Redesigning the rocket after testing it offers students the opportunity to apply their newfound knowledge to create a higher performing rocket, which in turn promotes further insight into aerodynamics. Students will also gain an experiential understanding of fundamental physics principals as they launch their rockets, such as stored energy, trajectory, and Newton's laws of motion.

Lesson Plan
Since construction is fairly quick, I like to conduct the lesson by constructing an example rocket in front of the class and explain key ideas along the way. (Talking about air and aerodynamics can be a little abstract since air is not visible, so I sometimes have the students wave their hands around to feel the air around them - that very same air is what affects the rocket).

1. Begin with the most crucial aspect of the project: the fins. As you cut out the fins, explain that their purpose is to stabilize the rocket's trajectory, or the path it follows through the air. Without the fins, any small disturbance in the air will cause the rocket to tilt off course and crash. Although students may experiment, explain that one or two fins will not work as well as at least three. One fin is unbalanced, and two fins can act like wings, which will create lift: a rocket that generates lift will fly sharply upward and stall. The fins must also be straight or else the air flowing over them will push the rocket off course. Finally, be sure the tape is applied firmly and smoothly to avoid any drag, or air that pushes against the rocket and slows it down.
2. Show how to bend the paperclip (or have it already bent as part of your preparation for the activity). The clip is most effective when the hook is pointed away from the rocket fuselage. Be sure to attach the clip securely or else it may rip off.
3. Build the launcher. The purpose of the craft stick is to keep the rocket away from the student's hands when launched. Young students (K-3) may have trouble attaching the rubberband correctly. The rubberband must be attached to the tip of the craft stick or else the rocket may smack into the stick.
4. Explain how to launch the rocket. Much of this is very intuitive. By pulling back, energy is stored in the rubberband, which can be used to fling the rocket forward upon release. The rocket's trajectory can be adjusted by changing the angle in which it is pointing.

The cost per rocket is about $0.05. All in all this project is very easy to implement and build. I've successfully conducted this project with kids in grades 1-5 (6th and up may not find any challenge here). Kids usually finish within 30 minutes, but with testing, redesigning, and any games you choose to integrate (Slingshot Rocket... Angry Birds?) the activity usually lasts for an hour. The kids like this project because they can build it a second time at home and share it with their friends, plus it's just plain fun to see rockets zip clear across a huge gymnasium.

Tips and Troubleshooting

• Use thick milkshake straws if you can find them.
• The straw can shatter if the rocket is propelled directly into a hard surface. If you're launching in a confined space, wrap the entire fuselage in tape (do this carefully to avoid lumps and flaps that could create drag).
• Establish a 'firing range,' in which students all stand on one end of the room and fire in one direction only. After students retrieve their rocket they should swiftly move to the side of the range before returning to this firing line. Picking up the rocket and pivoting to face the firing line can result in a crash-landing into someone's face.
• Bring blocks, targets with point values, or any other creative addition to transform aimless shooting into a game of accuracy.
• Try it at home before you bring it to class :)

If you're a teacher, parent, or otherwise involved with the lives of children, I hope you're now inspired to bring this simple yet highly engaging activity to the kids in your life. Enjoy teaching!