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Comment by syats | Hacker News Reader

The video is very good. i) It teaches basic gear-ratio concepts ii) it showcases an amazing repertoire of reduction modules, iii) it poses interesting questions regarding power transmission like: how much power is being dissipated throughout the system? or.. where is all the power of the motor going if you leave it running for 1 hour? iv) it motivates borderline philosophical question like: is the figurine at the end actually moving at all due to the gears? v) it has really good video editing / camera work

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On a practical level: no, it's not moving at all since all the movement is being absorbed by the slack between the gears.

There's a video of one of these constructions where the last gear is bolted to a wall or something.

Might be think of “machine with concrete” https://m.youtube.com/watch?v=5q-BH-tvxEg

I feel like doing the project in Lagos is going to confuse people but when you put the final gear bedded into concrete that sort of gets the point across

Yep, that's exactly it, thanks!

And as per that top voted comment:

The question of whether the last gear will break the concrete is moot. The gears themselves will erode away to nothing before they get a chance to apply much torque to the final gear.

I think that the same argument can be made to this Lego demo as well ;-)

If we consider the gears a perfect mechanism with no loss due to friction or wear then yes, it moves. Probably in a sub-atomic scale, but yes.

Unless space-time is quantized.

My mind just exploded. Would you have to breach a threshold to jump to the next state?

From my understanding, you start with a 0% chance to be in one state and 100%[1] to be in the other. Then the probability starts shifting more and more, till it is the other way around.

At least that is what I think it is, due to me having a very limited amount of knowledge in quantum physics. If a expert could confirm/deny my reasoning, it'd be appreciated.

[1] That is probably an exagerration as it would likely span more than just 2 possible states at any one time, but I chose two as a way to make it more understandable.

It’s true for converting liquid into gas.

So we could measure its movement in arc-Plancks?

Assuming the query [10^100 planck lengths to lightyears] is a correct interpretation of the question, a tooth on the first gear would need to move ~10^49 light years (well, in a circle) before a tooth on the last gear moved 1 Planck length.

I am less familiar with arc-Plancks, but I assume that is sufficient to say "the last gear doesn't move".

Yeah, and also this is material for kids and something we already teach them at schools and not "intellectually stimulating" stuff for HN.

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