Intro: Bike Wheel Wave Machine!
Wave back in the day in 1987, Norman Tuck made a beautiful kinetic sculpture he called "The Lariat Chain." Showing unique wave patterns that writhe and ripple through a long chain in unexpected patterns of movement, the motorized exhibit was wonderful. Standing waves and interference all came together in this wonderful dancing chain. It now lives in the Exploratorium, and is an amazing introduction to wave propagation and kinetics. And so, naturally, we wanted to make it for under $20 for our classroom and now you can too! Wave hello to this new kinetic curiosity, as it is time to make a wave machine! This one will truly forever make me go, "Whoa."
- What: Bike Wheel Wave Machine
- Concepts: waves propagation, interference, physics, kinetics
- Time: ~ 2 hours to make
- Cost: ~ $20, way cheaper if you have chain
- Old bike wheel
- 3 eye hooks
- Wingnut (optional for bike wheel)
- 2 washers (that fit your bike axle)
- Wood for base
- Dowels or 2x4 for support rods
- Beaded Chain w/ connector (I used about 20')
- Screwdrivers (for removing bike wheel)
- Wrenches (if needed for taking out axle)
- Sander or sandpaper
Let's do it!
Step 1: Remove Tire and Axle
Let air out if you need, and remove your tire from your bike wheel using a pair of flat head screwdrivers or bike tools if you have them. Here's a guide on removing your tire if you want! After that, unscrew the release for your axle and take it out. Mine was rusted and popped off, so I replaced it with a wing nut. You can ditch the tire, but keep the axle for the next step.
NOTE: You're going to put the axle back in later, so make sure not to destroy it in its removal. :)
Step 2: Metal Assemble!
After you've removed your axle, replace it with an eye hook and a washer threaded through on each side. Screw on a wing nut on the end to make sure everything fits and is secured. You'll have to undo the assembly to secure it to the supports, but it's good to check that it all works out.
Step 3: Make a Base
We need something to mount our bike wheel on. I started with some 3/4" plywood, and cut a 16" x 9" rectangle, and sanded down the corners. The actual space you need is much smaller, but it's nice to have a big base for when we mount it on the wall.
Step 4: Adding the Supports
To add your supports, first measure the radius of your bike wheel. In our case, the radius is ~ 11" so if we cut our supports at 14" we will have some open space at the back. Measure and cut your supports to the appropriate length.
Then measure the distance between your eye hooks on your metal assembly. This will be how far about you want to set the middles of your supports on your base. Drill them in so that they are parallel to each other, and then you're all set!
Step 5: Drilling in the Eye Hooks
Choose a drill bit that is slightly smaller than the diameter of your eye hooks. Drill in to the two dowels, and then start with screwing in one eye hook with your hand or using a screwdriver as leverage. Re-assemble your metal assembly, and then screw in your other eye hook on the other support before finishing off with the wing nut to keep everything in place.
At the end, screw in an eye hook directly in between the two posts. If you need, you can put a nut in the back to hold it in place. This eye hook will act as a guide for our chain as it spins.
Step 6: Mount and Attach Chain
Oh you're so close, how exciting! Choose where you want to mount your wave machine. I chose an area about 12' up to allow for maximum chain drooping. I drilled holes in the side, and zip-tied it to a grate high up. You will probably be drilling in to the wall, however, so make sure to get it level.
Choose and cut your beaded chain to the right length (I like just barely touching the floor), and feed it through the central eye hook and around your bike chain. Attach it using the connector! You should then have a full assembly like that in the fifth picture.
Step 7: Give That Wave a Spin!
Give a big ol' pull down on the side of the chain that comes off the front of your wheel (not that goes through the eyelet). You'll start to see the amazing standing waves, that propagate throughout your spinning chain and move as you touch and interfere with them. It is an amazing dance of loops and curves, and you'll never get the same motion twice. There's some more information on standing waves here, and wave propagation here.
You are bound to surprise yourself with what you'll see, all the gentle hum of the chain spinning round. A word to the wise, you'll find that you should only pull down on the side away from the wall, or else the chain will fall of it's track. If you want to be able to pull both ways, you can add a second supporting eye hook in front (with some extra support material), or make taller walls on the wheel.
Show us what you forget out in the comments below!
Keep exploring, have an amazing time, and just remember to wave.