When this curious contraption is switched on, an inner circle of white balls appears to be rolling inside the outer circle, but that's actually not the case at all. Below is a video explaining this circular motion illusion. Learn more about the mathematics behind it, specifically Copernicus’ Theorem, and the ingenious hypocycloid mechanical gear design by Girolamo Cardano (1501-1576) over at The Kid Should See This.
Michael Gardi says, “There were probably millions of CARDIACs (CARDboard Illustrative Aid to Computation) distributed to high schools and colleges in the late 60s and early 70s. Heck even my little high school in Northern Ontario got a bunch of them. But they are all but impossible to find now, so here is the next […]
A light box is an excellent tool for illustrators. It allows you to place a sheet of paper with a sketch on it, then place another piece of paper on top of it, and trace the original drawing. A lot of artists do a pencil sketch on a sheet of paper, then use a nicer […]
The creator of the CodeParade video channel made an interactive pushbutton busyboard for his toddler. He bought a bunch of knobs and switches, wired them to an Arduino, LEDs and beepers, and put them in a craft box. It has a simple mode, in which pushing a button triggers a sound or light, and an […]
Things break, and even in this disposable world, there’s a need to fix them. Up until recently, that’s been the crusty bottle of glue in your junk drawer, which is just as liable to coat your fingers as the thing you actually want to repair. Looks like there’s finally a Star Trek-level solution on the […]
Paying for things is all too easy online these days, and that’s why managing your money has gotten so hard. We’ve all done it: You sign up for a streaming subscription or gym membership, blow past the free trial date, and it becomes a part of your monthly expenses. Some of us juggle so many […]
We all know those gifts we get “for the kids,” the ones that parents are secretly more excited to open. Drones are a perfect example, but there’s a model out there that really doubles down on that appeal. Introducing the Space Fighter Building Block Drones, a series of space fighter drones that are a blast […]