This pendulum wave was a project for my grade 12 portfolio class. It was a self led assignment, so we were allowed to make a piece of our own choice. I had seen videos of pendulum waves before, and we were studying pendulum movement in physics, so I decided that this would be an interesting project.

I made the design to use two of my favourite materials, metal and wood. The wood for the beam and the base, along with the eyelets can be purchased at Home Depot. The heavy thread and maple spheres were from Michael's.

This project took about 10 hours to complete, and the cost was under \$50.

[I've included some videos of it in action in the conclusion]

## Step 5: Step 7

I figured out the lengths of the pendulums after having built the frame, which is probably backwards. You would be best off creating your pendulum lengths before making the frame so that you can build the frame to fit them exactly.

This is the calculator that I used to pick all of my pendulum lengths, credit to Paul Liu at hippomath.blogspot.ca for creating it: CALCULATOR (you can pick number of pendulums and set limits for sizes, super helpful)

## Step 6: Conclusion

Overall, building the pendulum wave went by very quickly. The longest part was probably stringing the pendulums up, because you have to be very specific about their length and avoid any twisting.

The result is a lot of fun to play around with. It goes through about 2.5 cycles before it gets out of sync. Because I didn't build my frame as a curve for compensation, the pendulums sit on an arc. I really enjoy the way it turned out, if I were to do it again I would probably make it a bit smaller so it could sit on my desk.

<p>My son wanted a smaller one for his office, so I played around with the calc finally using<strong> gamma=45</strong> and <strong>n=45</strong>, the result cycles a bit quicker but its still very mesmerising.</p><p>The resulting footprint is about A4 size, sizes attached for those interested.</p>
<p>The steel bearings look really good on it.</p>
<p>I used a 30mm plastic bead, which although a bit light, looks quite cool in sunlight. I used a pop rivet to hang the bead on <em>invisible</em> nylon sewing thread. You don't actually see the hanging thread when its indoors unless you peer quite closely. Each bead has a fixed point in the smaller 1.5mm hole and a tunable point in the larger 4mm hole using a section of bamboo skewer. </p><p>Next up, is filling the bead hole with something heavy and cold so as not to melt the nylon thread.</p><p>The curve in the upper wood strip was made by soaking the wood in water for 2 days and bending it around nails nailed into a plank for the form. The nails leave an indentation in the soft wood, so not such an ideal idea, but its quick and easy. </p>
<p>Looks great!</p>
lol nice sketches for instruction haha
<p>Thanks, they were fun to come up with after the fact! I usually forget to take pictures of my projects while I am building them.</p>
<p>Wow very nice instructable. I will make one for myself and a mini model for my science teacher. I bet she will love it.</p>
<p>Excellent! You've got my vote!</p>
<p>Thanks!</p>
<p>At first glance thought Newton' Cradle. Nice job!</p>
<p>Thanks!</p>
Nice build, love the aesthetic! I made one of these a couple of years ago. It kept a good sync for 5+ minutes. The key in achieving this is very precise adjustment of string lengths and using string that is completely inelastic, and note made from tangled fibers. Secondly using heavier weights reduces the effect of drag.<br>To achieve this I used guitar pegs, metal wire. As weight I used heavy, big ball bearings. The ball bearings are also very uniform in both shape and weigth. (these adjustments will make the setup more costly ofcourse)<br><br>For physics guru's: among others, this setup allows you to show the limits of a simple pendulum model. Perfect lengths can be calculated by intoducing a good model for drag.
<p>Cool! Do you still have it? I would love to see a photo of the setup.</p>
<p>Cool kinetic sculpture for the coffee table.</p>
<p>Great build. Beautiful and simple design. I may have to build this with my kids when they get a little older. </p>
These are great! I've always liked them!

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Bio: I am a third year Architecture student who is interested in art, design and engineering. I am always looking for new projects and new ways ... More »
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