Longtime readers of this blog– both of them– know that here at Zheng Labs we’ve got a couple of rugrats running around the place. The older one’s in high school now, and has a practiced eye roll that earns perfect 10’s even from the Romanian judges. She’s not the subject of this post, although you can see photos of her pupal stage here and here, and some free 3D printable models to boot.
No, my friends, this week we bring to you the chronicle of my younger spawn and his adventures at the elementary school science fair. Each year his school puts on an open house for prospective families where they might explore for themselves the Hogwarts-like environment at one of Wisconsin’s fine public charter schools.
This open house features a gymnasium full of the kids’ long-term science projects, and is always a treat for those inclined to make things that go kablooie with papier maché, baking soda, and a little CH3COOH.
In years past procrastination and lack of interest have led my son to flail helplessly in front of a sloppy trifold when the time to present his project came, and this year we were determined not to repeat that particular learning experience. We got started early, enlisted a 3D printer, and won the science fair.*
*on “winning:” the event is actually noncompetitive and the school doesn’t give out prizes. I’ll define winning as spending a couple hours in the basement with my son, teaching him how motors and voltage and switches and soldering irons and burn creams work. Plus the look of unadulterated joy on Xiao Zheng’s face when the project worked: priceless. Scroll down to the bottom of the post for the big payoff video.
Also, the kid who actually won the science fair was the one with the trifold cheerfully labeled “Exploring Uranus.” That kid’s going places and has either fantastic or clueless parents.
Astute readers may have surmised that this year’s theme was space science, and the thrumming gymnasium was packed, absolutely packed with elementary school children wearing astronomy-related costumes. One kid was a dead ringer for Carl Sagan (red turtleneck included). Galileo and Halley’s comet were easily identifable from across the room. One young man made a fantastic Pathfinder rover hand puppet, a young lady was fetchingly dressed as the day and night cycle complete with helium balloons tied to her pigtails, and much aluminium foil was spent in the pursuit of knowledge.
Soviet science was well represented, too. The neighbor kid dressed up as Sputnik, and there was even a kid in full bright-orange Yuri Gagarin drag. Imaging getting that costume past the a 1950’s school board here in Appleton, Wisconsin, hometown of national disgrace and Ted Cruz lookandthinkandsoundalike Senator Joe McCarthy.
I’d post photos of the science fair, but! Kids’ privacy issues. You know the drill. Local parents: if you’d like to share a photo of your kid’s costume, send it my way.
好久以前, back when Zheng himself was xiao, Dad and I spent many evenings in our basement laboring on school projects. In all fairness it’s safer to say that Dad did the heavy lifting and I just provided parameters, but man those projects were the envy of the other kids in elementary and middle school. I wish I had photos of the tornado diorama, or the sculpture of Zeus made of toilet paper, shellac, and Ivory soap flakes (!) or that Roman aqueduct we (Dad) made out of grout and PVC. Or the paper bag mountains with joint compound glaciers. Or the passive solar house model made out of foamboard reclaimed from the dumpster at work.
Thanks Dad, for doing those projects with me. I’m doing my best to pass your creativity down to your grandkids. Cir-cle of liiiiiiiiiiiiiiiife!
But I digress. This is a 3D printing blog first and foremost, and you’re here to read about the process of creation.
We got the trifold part of the project out of the way first, and settled into working on the costume part of the presentation. Our challenge: making a wearable model of Venus. Xiao Zheng’s first idea was to hand-letter the word “VENUS” on a piece of cardboard and hang it around his neck. He’s literal that way sometimes.
A planet-like sandwich board was also considered and quickly discarded as “stupid” and uncomfortable to boot. We gnashed teeth and rended garments for a while before remembering that his bike helmet has a GoPro mount on it, and would be a perfect platform on which to place a model.
The model of Venus itself is nothing fancy, just a lightweight ball of bubble wrap shrouded in painted tissue paper. It masses approximately 116 grams. The actual planet Venus masses 4.867 × 1027 grams.
I introduced my son to the joy of inadvertently huffing spray paint fumes in the garage, which he liked. Maybe too much.
Just attaching Venus to a helmet’s really not enough when the other kids are dressed up as Saturn V rockets, so we had to take it to the next level by making the model spin. I’ve got a bunch of old DC motors kicking around because of course I do, but we quickly realized that even if we could attach the motor’s axle directly to the model, it’d spin way too quickly.
We needed to slow the spin and the solution, as it is to so many things, is gears. Fortunately, I’ve already got some at the ready.
So a few minutes’ modification in Maya and we’re off and printing. Pro tip: gaffer tape works astonishingly well as a print surface for ColorFabb’s PLA/PHA. Note that there’s a cup integrated into the top of this gear to give the planet more surface area for adhesives.
Next we’ve got to get the gears onto the helmet, and fortunately there’s a GoPro-compatible mounting system in the Forge. A few more minutes of vertex wrangling and a couple of test prints and the mounting system looks like so:
(You can download the models here if you’d like to take a peek at them.)
The rotation is controlled with a momentary switch hidden in the kid’s pocket. Hold the button down and Venus spins faster and faster. Of course, my kid’s teachers aren’t pants-wetting bigots and he’s white as Wisconsin snow and not named Ahmed, so nobody batted an eyelash at this suicide-bomber-looking pushbutton setup. It’s even RED.
Fun fact: Venus’ day is 243 earth days long. I learned this from the aforementioned girl dressed as the day-night cycle.
Everything’s gaffer-taped together to insulate the solder joints and the wires are hidden under clothing.
The project survived the entire night on one set of 4 AA batteries and finally met its demise when my son, in an all-too-typical display of spazzy exuberance, head-butted the kid dressed up as a Soyuz capsule during cleanup and Venus went spinning across the gym floor and into the hallway.
Lao Zheng out. Thanks again, Dad, for teaching me how to do a science fair project right.