For my project, I decided to create a wave machine demonstration, illustrating how wave particles move and how wave speed and mass are related. Using duct tape, two shower totes, kabob sticks, clay, a scale, and small weights, I created a wave simulator. I first laid out a long piece of duct tape and put evenly spaced kabob sticks on the tape. Then, I made clay balls with the same weight and put them on both sides of the kabob sticks. I attached the strip of tape with the kabob sticks onto the shower totes. Finally, I created tension on the tape by putting small weights, in my case some nail polish, in the shower totes. The clay balls represent wave particles, and you can see that when I create a wave in my wave machine, the clay balls only move up and down. This can help teach people the characteristics of a transverse wave: wave particles move perpendicular to the wave motion. One of the biggest issues I had was finding the right weights to put on both ends of the tape, because I knew they had to be small enough to bring to school but stable and heavy enough to create enough tension on the duct tape. I tried using storage boxes, water bottles, and dumbbells before deciding on shower totes. Another problem I encountered was creating clay balls of the right weight. Initially, I had made balls that were too light, making the wave machine not work as well. In the end, I made clay balls that weighed 5g, which made the demonstration work much better.
This project was inspired by a YouTube video.
Wave Machine Demonstration. Dir. Jonathan Sanderson. Perf. Alom Shaha. YouTube. National STEM Centre, 18 Nov. 2014. Web. 18 Oct. 2015.
Step 1: Collect All the Materials.
You will need a roll of duct tape, clay, kabob sticks, a scale, two shower totes, and some nail polish or other small weights to put in the shower totes.
Tote picture courtesy of: http://www.amazon.com/Creative-Bath-Products-Shower-Caddy/dp/B00KQHL5A6
Step 2: Lay Out a Long Piece of Duct Tape.
Depending on how big you want the wave machine to be, the length of the tape may vary. In this picture, I have attached it to two storage boxes; however, later, I change them to shower totes as they worked better.
Step 3: Spread Out the Kabob Sticks Evenly.
While it is not important to have the same exact width between each kabob stick, the spacing should be approximately equal.
Step 4: Make Clay Balls That Weigh the Same.
Use the scale to weigh the clay. I used clay balls that weighed 5g; they should weigh about 5g or more, because when I used clay balls that weighed 2g, the wave machine did not work as well. As you can see here, I took the small original yellow clay balls off and remade the balls so that they weighed more.
Step 5: Put the Clay Balls on Both Ends of the Kabob Sticks.
Step 6: Cover the Whole Thing With Another Piece of Tape to Make the Machine More Durable.
While the machine seems to work better without the tape over it since it gives the kabob sticks more freedom of movement, the tape does help keep the sticks in place.
Step 7: Attach It to the Shower Totes.
Make sure they are strongly attached on both sides, because once we add tension to the tape and the shower totes aren't attached properly, they can easily be ripped apart.
Step 8: Create Tension on the Tape.
Add books or any other kind of weights in the shower totes to create tension in the tape.
Step 9: You're Done!
Tip one side to see the wave machine in motion. You can see that the clay balls themselves are only moving up and down, showing how transverse waves have wave particles perpendicular to wave motion. This is similar to the human "wave", where people stand up and down to create a wave that looks like it is going through them.
Step 10: Bonus - Take the Clay Balls Off on One Side of the Wave Machine.
This will show how as mass decreases, wave speed increases. Mathematically, mass and wave speed are inversely proportional from the equation,
v = square root (T/(m/L)) where v = wave speed, T = tension, m = mass, and L = length