Introduction: Giant Portable Wave Pendulum

About: Summer camp assistant director by day, maker all the time. I love making stuff and I have a YouTube channel that shows how I do it. Come check me out :)

This video shows how I made a giant (about 5' tall), portable (disassembles into a 5' x 5" bundle), wave pendulum. It is a great tool for demonstrating physics, and a lot of fun to build and play with.

Unfortunately embedding videos is still not working for me, so here is a video of how I made it:

How to make a Giant Portable Wave Pendulum: Simple Welding and Electromagnets!

Step 1: ​Step 1: Cutting Conduit

Cut 4 pieces of 1” conduit to about 6 inches with a 30 degree angle on one side. I 3D printed a jig to mark out 30 degrees around the tube. Also cut 2 pieces of 1” conduit to about 6 inches with 90 degrees on both sides.

Step 2: Step 2: Welding the Brackets

For each of the two brackets. Weld two 30 degree pieces together to make a 60 degree “V” shape then add the last piece so that it connects in the corner as seen in the picture and video.

Step 3: Step 3: Clamping System

In order to create a clamping system so that the legs don’t slide out of the brackets I used nuts and bolts.

First, drill a hole in each piece of 1” conduit using a step up bit.

Second, weld a flange nut over each of the holes. I used a flange nut instead of a regular nut because the built in washer makes it easier to weld without melting the nut

Lastly, screw in the bolt.

Step 4: Step 4: Electromagnets

These aren't completely necessary, but I think they make the project way cooler. All I did was velcro a couple of electromagnets to the legs, and then wire them up in parallel so that they both turn on and off at the same time.

I then took a plank of wood and screwed in a couple metal plates to stick to the magnets. This way I can set up all of the balls and then just hit one switch to let them all go at once.

Step 5: Step 5: Hang the Pendulums

I used Cue balls as pendulums, but any weight will work. I then hung them up according to the lengths in this chart I made. In order to give the strings even spacing, I welded a stip of steel with holes in it to the center brace.

Step 6: Step 6: Assemble and Test

Now that all of the pieces are done, assemble the device and test it. If done correctly, the balls should start by swinging all together. Then the pattern should start to look more chaotic then less chaotic in cycles. This demonstrates the frequencies of waves.

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