Tennis, Anyone?

Substitutions can be made for almost any of these materials:

• string
• yarn
• straws
• tape
• paper towel tubes
• balloons
• rubber bands
• glue
• tinfoil
• paper clips
• plastic wrap
• paper & pens
• bendable wire
• small bouncy ball

1. Identify the Problem
   • The most critical step of any engineering challenge is to understand the problem you are trying to solve.
   • The problem you are trying to solve is to make a racket out of everyday materials that reliably and accurately hits a target.
2. Collect Materials
   • Start collecting materials for your racket.
   • Don’t have all of the items on the list? That’s okay – you don’t need all of them. Look around and see if there are other materials you can use instead or do without.
3. Brainstorm Designs
   • Look at pictures of a tennis racket online. What do you notice about them? Why do rackets have mesh (crossed strings) instead of a solid surface?
   • Did you know that the crossed strings of a tennis racket create an elastic surface that moves slightly with the ball? Rackets with higher tension (less elastic strings) gives a player more control on where the ball goes. Rackets with lower tension (more elastic strings) gives the player more power to make the ball go farther or faster.
   • As you design your racket, think about:
     • How fine or loosely spaced should the weave of your mesh be?
     • What materials can you make the mesh out of? Try out different materials.
     • How can you attach the mesh to your racket frame so it doesn’t pull apart when you the hit the ball?
     • Does the surface area of your mesh matter? Why or why not?
     • What’s the best thickness for the handle?
4. Build It
   • Start building! If possible, take pictures of the materials as you build. Maybe one at the beginning, one during the process, and one at the end.
5. Test It
   • How far you can hit a ball with your racket?
   • Make a target. Tape a piece of paper of paper to a wall or door. Can you hit the target?
   • Add a bullseye to your target – can you hit that?
   • Do you have a partner to play with? Can you volley a ball back and forth with your rackets?
6. Share Results
   • Share your results and your design with your teacher or parents.
   • Did it work like you thought it would?
   • What design changes would you make?
7. Make Changes and Try Again!