Gear Up Your Gear Knowledge With Gears

Gears are fairly straightforward way to couple rotational motion, and the physics topics required to understand them are encountered in an entry level physics classroom, not a university degree. But to really dig down to the root of how gears transfer motion may be somewhat more complex than it seems. [Bartosz Ciechanowski] put together an astonishingly good interactive teaching tool on gears, covering the fundamentals of motion up through multi-stage gear trains.

Illustrating the distance traveled at different points on the disc

The post starts at the beginning – not “how to calculate a gear ratio” – but how does rotational motion work at all. The illustrations help give the reader an intuitive sense for how the rate of rotation is measured and what that measurement actually represents in the real world. From there [Bartosz] builds up to describing how two discs touching edge to edge transfer motion and the relationship of their size on that process. After explaining torque he has the fundamentals in place to describe why gears have teeth, and why they work at all.

Well written explanatory copy aside, the real joy in this post is the interactivity. Each concept is illustrated, and each illustration is interactive. Images are accompanied by a slider which lets you adjust what’s shown, either changing the speed of a rotating gear or advancing the motion of two teeth interlocking. We found that being able to move through time this way really helped form an intuitive understanding of the concepts being discussed. This feels like the dream of interactive multimedia textbooks come to life.

Lose The Beer Belly By Brewing Beer

If you’re milling your own grains for that next batch of beer you might be able to melt all of those extra calories away while you’re at it. [Eucherboy1] repurposed an unused exercise bike to power his grain mill. The propane tank is serving as a weight to hold the base of the mill in place; it’ll be used later when boiling the wort. A belt transfers power from the bike to a wheel replacing the hand crank on the mill. Check out the video after the break to see [Euchreboy1] working up a sweat. We think there’s much room for improving the gear ratio of the setup. Or he can just man up and push through the pain.

We’ve gotten used to seeing ways to power a bicycle, like using wood-fired steam, or even by incorporating a chainsaw. But the hacks that use a bike as a power source are a bit less common. Our local hackerspace made a bicycle blender a while back. Got any projects of your own that are bike powered? Send them our way!

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