Can Teachers Build a Physics-Go-Round?

The Joy Wheel, at the now mostly defunct / relocated Playland at the Beach. Read on for a vivid, gorey memory of physics experiments by a San Francisco teen employee there decades ago. Photo courtesy of Mike Winslow's  Playland at the Beach

The Joy Wheel, at the now mostly defunct / relocated Playland at the Beach. Read on for a vivid, gorey memory from decades ago by a San Francisco then-teenaged employee. Flashback photo courtesy of Mike Winslow’s Playland at the Beach site.

How would you build a giant turntable or merry-go-round for the physics classroom? I was recently sent a discussion among teachers from the Exploratorium’s Teacher Institute on this very subject. It reminded me of the summer before my senior year of high school, when I took a physics class at Caltech with a juggling grad student who looked a lot like Jesus. Our best lesson of the summer? He took volunteers to a nearby park to see him and his pal juggle on a roundabout, and a few of us got to join him on the rotating platform. He gave us a playful metaphor to understand the alphabet soup of the calculus-rich vector exercises we did in the classroom.

Back to this teacher’s query. Ben posed the original challenge:

Our physics teacher and I have been fantasizing about having a large turntable on which students could explore a variety of concepts. Ideally we would like a surface around 3 or 4 meters in diameter that will stay flat, turn smoothly, support three or four high school students, and be sturdy enough to survive the wear and tear of years. Have any of you built a large turntable for class demonstrations? I would appreciate any plans, suggestions, or cautionary tales. It’s a long-term goal. We’ve been going round and round (so to speak) about size, materials, safety, bearing setups, used vs. new, placement etc.

Mandy suggested our oversized spin-art machine, but Ben needed something a bit slower. He defined it more clearly:

Courtesy of

We want the students to study motion on a rotating surface, from various perspectives. I’d like to use it to demonstrate the Coriolis effect, for example.

We would like students to be able to sit on it, throw and roll balls between them, and film the ball’s motion from on, above, and beside the surface, both moving with the surface and not moving with it.

It needs to be strong enough to support them, and large enough to be able to observe the motion of objects moving above the surface for some distance.

Ellen Koivisto of Asawa School of the Arts in San Francisco chimed in with a clever, STEAMy suggestion:

Talk to your theatre teacher/s and tech people. Turntables have become common set items again in recent decades (after Les Miserables). They were often built for Victorian melodramas, then fell out of favor with the rise of movies and kitchen sink naturalism.

I’m doing a show right now that uses a relatively small turntable — 11′-6″ in diameter. There are three concentric rings of casters that take the weight. I believe it’s two layers of 1/2″ ply, laid perpendicular to each other and glued together. One person can push it with their foot, or there are pole holes so a person can stick a metal pole into the hole and pull the turntable around. It moves smoothly and easily.

I did a show once with an 18′-diameter turntable. That required more people to move and bigger casters, but it was lovely to work on. I haven’t done a motorized turntable yet, but there’s tons of info on making and using them in technical theatre magazines and websites and books.

Caren Kershner similarly suggested checking in with the old Creede Repertoire Theatre in Creede, Colorado about how their three stages mounted on a turntable function.

While looking for images for this post, I found this detailed how-to on how Texas A&M’s Scene Shop built this rotating stage turntable for its production of Th3 B3ggar’s Op3ra.

Texas A&M's Scene Shop built this rotating stage turntable for its production of Th3 B3ggar’s Op3ra." Read more about how they built it here.

Texas A&M’s Scene Shop and its rotating stage turntable in progress.

Raleigh McLemore had lots of ideas:


Photo: wikipedia

My first thought was that you could build off of a platform like a playground merry-go-round. Some simple welding or carpentry might be all that it takes to either remove the uprights or add structure to them to build a platform that a student could safely stand on. You are working with bigger kids and some of the cheap (about $750) small structures may not have enough carrying capacity. Larger built spinning structures are heavy and expensive (around $2K). Outside chance your local parks department might have a broken one, or one that is in storage after a playground change up.

Another idea might be to start with a junkyard car wheel and wheel bearing. A front wheel kingpin might be pretty cheap and could be located vertically in a strong base with the wheel and bearing slipping over the kingpin to become a center to the car wheel spinning on it horizontally. Not sure how it would happen, but I’m sure the car wheel would be a very strong point to begin to weld or assemble a wooden structure upon. I haven’t thought it through very far but I would start with buying a wheel with a wheel bearing(s) and a kingpin if they were reasonably priced.

If a kingpin doesn’t seem right then I would look for an appropriately sized shaft to support the wheel and bearings. Perhaps even a hardwood axle could be fashioned although first thoughts seem to me that it wouldn’t be strong enough. Any upright axle that could be located into a solid plywood base would get you started. The junker car wheel bearing would fit upon the upright axle, the wheel would then be the spinning base of the structure. Done correctly you should have a stable spinning base. The platform couldn’t be too heavy or unbalanced, or it would wiggle and wobble. Putting additional support wheels around the outside of the large spinning platform might make the platform more level and add to stability.

Seems a bit elaborate, but I suppose you could use a dryer motor and belt to spin the wheel by mounting it on the plywood base at a distance to put tension on the horizontal spinning wheel using the dryer belt. You need guards and a speed control for this. What with the variable loads this could be a mess and deserves a lot of thought unless you can get the junk for free. Done poorly you could have a fire or a short.

Last, I wonder if you could hang something from a rafter/joist support (use rope? wire rope?) and put some good wheels around the outside of the platform so that the center is supported from a high point and the outside edges are held up by the wheels? This might be reasonably cheap if the overhead support is equal to the load. This might not be very smooth or stable for the experiments you have planned. Not sure how you would have a smooth controlled motion without a rail to guide the wheels. You wouldn’t have a clear center with this, the support rope popping out of the center of the platform.

Detail of a mural hanging at Playland Not at the Beach. Photo by Jef Poskanzer.

Detail of a mural hanging at Playland Not at the Beach. Photo by Jef Poskanzer.

Raleigh wrote again a little later to reminisce about his time working the Funhouse “Joy Wheel” at San Francisco’s old Playland at the Beach.

This thing was a very large flat, slick, spinning disk with about 20–25 folks climbing on, sitting as close to the center as they could squoosh. My job was to control the speed and spin the disk as fast as it needed to go to spin the folks off and have them slide hopefully to the padded wall and away from the spinning wooden platform. It was lots of fun until folks frantically grasped others and took off a large clump of people who slid off together. The resulting crush of humanity wouldn’t fly off of the disk completely and over and over again somebody would get jammed into the edge of the wheel, unable to move away due to the others being pushed against the wall. I had a “panic stop” button but it really didn’t stop the device very quickly when I hit it. Very gruesome injuries would sometimes occur, never life-threatening, but bloody. My job was to clean that up too.

When the midway had no customers, and I was free to move about the site freely, I used to roll stuff across the slick Joy Wheel surface, pour water at different places and occasionally even be able to anticipate where my experiments might exit the wheel. I remember thinking that somehow if I threw a dart in the air over the spinning disk the dart would begin to rotate with the spinning wheel before it hit…it is still surprising how much I want the disk to alter the trajectory of the dart, although I know it can’t.

From Raleigh’s description and the photo at the top of this post, I’m finding myself wishing there were a giant rotating disk in every city. It sounds like such fun! Except the bloody part. If you can’t quite make out the sign in the top of that picture, it reads “The best cure for blues is joy. Get cured here” (Also, who else thinks that might be Raleigh in the picture?)

We now turn to the Maker-verse. Have you built a large rotating disk? Can you share plans and tips for building it?

Incredible Aviation-Themed Desk


If you need a desk you can, of course, always buy one. Or you can make an excellent “normal” desk with right angles and the occasional rounded edge. On the other hand, you could make a truly exotic aluminum covered aviation-themed desk like the one pictured above.

The results look very good and well polished. Naturally, results like this don’t come about easily. According to the imgur part 1 documentation of this project, 60 hours had gone into the project by the end of the “part 1” documentation. I hope to see “part 2” soon. Hopefully this will explain the finishing process.

The part 1 documentation, of which an abbreviated version can be seen below, goes through what appears to be most of the woodworking process. Like a real plane, spars had to be constructed, as well as rib members that were rounded off to give it an “aerodynamicish” look. The frame was then covered with a thin layer of aluminum .5 millimeters thick. Not seen in the documentation, but hinted at in the text, the final version has plastic pipes running through it for efficient cable management.


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If you’d like even more information and comments on this project than the image set gives out, it was originally seen here on Reddit.

Rana: A Biologically Inspired Hexapod

Rana, which is Italian for “frog,” is really an interesting six-legged robot design. The locomotion, which according to their writeup, has never been used before and combines the walking methods of an ant and a frog.

This kind of locomotion, as opposed to three-servo based ‘bots that simply rock back and forth allowing the front and back legs to move, requires ten servos. Two servos are attached on both pairs of front and back legs, while the middle legs receive only one servo each.

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Although the robot’s motion is complex, the mechanical housing and legs are kept simple.  Pieces of wooden rod are used for all the legs, while a larger piece of balsa wood (presumably for weight savings) is used for the body. As no other linkages are used, this may be a surprisingly easy walker build for those wanting to build one.

Although it looks like there is a plan for the robot’s walking gait, the code is not released yet. As the write-up states that “programming is one of the hardest steps,” the code is apparently not done or not to a state that the author is ready to let others look at. Hopefully we’ll see some further development on this interesting project!


How-To:Quick & Easy Digitigrade Stilts For Halloweeen


Halloween is fast-approaching, and makers everywhere are gearing up. They’re strolling right past the aisles full of mass-produced costumes, heading instead to the hardware aisle, the fabric section, or the arts & crafts department, gathering materials for their own custom costume creations.

One item that can play a starring role in a variety of custom-made costumes is a good set of digitigrade stilts. These are stilts that imitate digitigrades, which are any creatures that walk on their toes (or digits). This includes animals like cats and dogs, as well as mythological creatures like werewolves, dragons, fauns, and minotaurs.

A custom set of these stilts can be pretty expensive, not to mention hard to find. But with a little elbow grease, a quick trip to the hardware store, and a Saturday afternoon, you can make a pair of your very own digitigrade stilts for a fraction of the cost.

I recently put together a pair of my own digitigrade stilts over the course of a few hours, and afterwards I made this quick video to show you how it’s done.

Here’s what you’ll need to make the stilts:

  • 2x)  1″x4″x2′ boards
  • 1x) 2″x6″x4′ board
  • 1x) Box of 1 3/4″ wood screws
  • 8x) 1″ machine bolts with matching nuts
  • 24x) Washers to fit machine bolts
  • 8x) lock washers to fit machine bolts
  • 4x) 2′ sections of shelving brackets
  • 4x) 3″ x 3″ T-Plate connectors
  • 2x) Adjustable velcro straps
  • 1x) 4″ PVC coupler
  • 1x) length of pipe insulation foam
  • 6x) zipties
  • 2x) 24″ bungee cords
  • 1x) Old pair of shoes

You’ll also need these tools:

  • Phillips screwdriver
  • Electric drill with drill & driver bits
  • Pliers (or socket set – used for tightening bolts)
  • Hacksaw
  • Miter saw (or handsaw with miter box)

For step-by-step instructions (and to see the finished product), check out the video below!


Jamie Locke: Beautiful Carved Mandalas



If you were at Maker Faire New York, you inevitably heard the news about the Dremel 3D printer. However, if you stopped by their booth you may have found yourself staring at something other than the printer. The beautiful and intricate artwork of the artists that Dremel brought in absolutely stole the show.

I stood for some time and watched Jamie Locke delicately carving mandalas into a ukelele. It was mesmerizing and inspiring.

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Jamie does fine dremeling of patterns into all kinds of things. From art pieces that hang on your wall, to instruments, straps, bracelets, or pretty much anything she can get her hands on. There are tons of great pictures and some videos on her site, but you may have better luck following her facebook page for more up-to-date art.

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I really have to congratulate Dremel on bringing in skilled artisans. So many of the nice tools are taken purely by their specs and the beautiful creations of the artists that use them take back stage. This was refreshing and wonderful!

DIY Upcycled Thrift Store Clock


I am an avid thrift store shopper and treasure searcher. I go as often as I get the chance, and I usually always find some neat trinket, vintage clothing or accessory, or piece of home decor. I have so many things lying around with all the best of intentions to restore them. Lately, I’ve made some progress by finally painting a mid-century dresser and some tables, but I’ve yet to complete a project as neat as Imgur user Holliciraptor (screen name props!).

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For her boyfriend for their one year anniversary, she decided to upcycle a $3 alarm clock she’d bought into an inspirational one she’d been eyeing on Etsy. Finding replacement parts for the clock on Amazon for $5.95, she went to work. She began by rendering the design of the clock in Photoshop to get an idea of what she wanted. Using a CNC router she had access to at work, she cut the pieces for the clock out of oak and used 6mm foamed PVC for the center, also cut with the router. She made a new face for the clock using Photoshop as well, which involved gold vinyl cut into the number 12 and layered to add dimension. Lastly the clock was stained and the brass rod was added for support, and screwed together.

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Jam Out On A PVC Percussion Organ

Jeremy Cook’s PVC Pipe Instrument uses plumbing and wood for a unique sound

Jeremy Cook’s PVC Pipe Instrument uses plumbing and wood for a unique sound

You’ve seen them in the street, buskers and musicians performing crazy acts and playing just about every kind of music from Gregorian chants to throwing down on a Didgeridoo. Speaking of weird instruments, PVC pipe drums have been exploding on the street-corner scene in the past few years and the trend seems to be growing.

Jeremy Cook’s detailed plans for building his PVC Pipe Instrument

Jeremy Cook’s detailed plans for building his PVC Pipe Instrument

Why not, they have a unique sound and are incredibly easy to build using a little bit of plumbing knowledge and some simple carpentry. In fact, maker Jeremy Cook and his Cousin Jackson (a musician) decided to build their own with a step by step tutorial on how to get the job done. First, a simple frame is hammered together with several holes cut out of the top edge. Different lengths of PVC piping are glued together and positioned through the holes for stability and accessibility. Next braces are screwed to the sideboards, which lock the pipes in place. Done, that’s it, you now have a musical instrument that sounds like you hammering out notes in a deep dark cave or in a vacuum chamber. Pair it up with a Theremin and maybe an old-school synthesizer and watch the crowds gather (or run in terror). Follow this link if you too want in on the PVC crazy.

Over-Engineered Ringbox


What do you get when you have a CNC router and your significant other has a beautiful ring that needs to be stored? Possibly this extremely engineered ring box. The video below shows how it works, but be sure to check out the video at the bottom of the build process. As the author puts it in the original Reddit post: “I had never touched a CNC machine or 3d modeling software. Probably not the best project for me to learn on, but it all worked out!” I would have to agree, especially considering that he claims this took over 500 hours of work and more than 30 hours of machine time.

In addition to the newly-acquired CNC skills, he (or his girlfriend) seems to be pretty handy with a chainsaw! Having done much smaller projects myself where I was able to chop down a tree, then finish what I wanted to build out of it on a machine-tool, this kind of process is extremely satisfying. On the other hand, I’d have to assume he didn’t forge his own aluminum for this box, but I suppose that’s acceptable.

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After reading some of the original Reddit comments, it appears the builder’s significant other is now classified as “fiance.” Congratulations to him on the accepted proposal, as well as making something awesome!

Laser Cut Room Divider


Recently, the folks at Trotec laser moved into a new larger office. This is generally a good sign for a business, but unfortunately there wasn’t a good area for guests to wait in, just a large open hallway. Marketing specialist Kristina decided to take matters into her own hands and make one herself. This was facilitated, naturally, by their office laser cutter, and the results in the gallery at the end of the article look great.

It’s great to see the pieces being made in the video below. I’ve got a little CNC router, which is awesome (and has the advantage of cutting in the Z direction), but the ease-of-use and potential cutting area of a laser cutter has always looked really appealing to me. You also generally don’t have to fixture anything with a laser since light is doing all the cutting.

To be fair, my understanding is that there can be some issues with fumes when using this kind of cutter, and I’m sure the laser elements can be sensitive. Also of note, if you want to do anything in 3 dimensions, it’s definitely limited. Still, getting great results like this with your project with what seems like very little effort has to make producing your creations so much easier!

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Gorgeous Wooden Table Built Using Only Hand Tools

Chris’s table was built using reclaimed wood and hand tools only

Chris’s table was built using reclaimed wood and hand tools only

So, what do you get your significant other for your 20-year anniversary? Traditionally, it’s usually something made from porcelain or platinum like dinnerware or jewelry. If you’re a craftsman like Chris (from Chop With Chris fame), you build an incredible dining room table made from reclaimed wood and rough-sawn lumber, cobbled together using nothing but hand tools. The chestnut base and supports were dovetailed and pegged together making for a sturdy foundation with notched pieces for the table’s top surface. The top itself was made using several walnut boards with chestnut edges and breadboard ends, which were joined together, sanded to perfection and oiled to bring out the natural beauty of the wood.


It took Chris 160 hours spread over six months to complete the build, which surprised his wife who considered the gift both beautiful and priceless. Chris is certainly talented with his woodwork and a step-by-step video was made to show what it took to build his dining table for those who would like to give it a try. See more in the videos and after this link.