Bryan Macomber, explaining how pull-back toy cars work:
Gears are all around us. Clocks, cars, bikes, even your printer has countless gears! For the purposes of this analysis, we’ll focus on two properties of gears: gears can be used to multiply torque and used to change speeds.
Why is torque important here? Winding the spring in this toy requires significant torque. But this is product for kids, so how can we make it easier for them? The answer is gears! Gears give the kids a mechanical advantage.
Detailed, animated, interactive illustrations (Bryan is a mechanical engineer and artist) make this and Bryan’s other explanations very clear. But maybe more impressive is the careful attention he gives to deciding what exactly to explain, step by step. Art is everywhere.