Making a Googol:1 Reduction with Lego Gears [video]

[syats]

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

[frabert]

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

[ainiriand]

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.

[lmilcin]

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

[simoneau]

See also "Machine with Concrete", by Arthur Ganson https://www.arthurganson.com/concrete-1

[dmos62]

I remember this art installation that was spinning gears setup in a high gear ratio and the last gear was cemented. When looking at it you couldn't help but picture the gears and the motor starting to grind against the resistance of the cemented gear, but the reality was that that wouldn't happen for many many years.

[zimpenfish]

https://www.youtube.com/watch?v=5q-BH-tvxEg

"With the motor turning around 200 revolutions per minute, it will take well over two trillion years before the final gear makes but one turn."

[rafaelturk]

Now put the motor on the back end and watch the first gear spinning at the speed of light!

- from youtube Timon Di Mare's comment

[throwaway_pdp09]

Were one to do this assuming hypothetical material that wouldn't break up under the stress, nor expand due to stress alone - hypothetical like I said - reversing it would cause relativistic expansion + general weirdness at the fast end. Wouldn't that expansion cause the gears to hbe forced apart and rupture, or something? I have a feeling it would somehow not but I can't imagine what would happen. They must expand, yet still remain engaged, which seems contradictory.

[ioulian]

Sorry to be a buzz kill, but AFAIK you can't "reverse" a worm gear.

[the_cramer]

I wonder how much energy it would take to spin it at all

[danfromberlin]

It's safe to say that any human capable of rotating that lego man, even just a single degree within his or her lifetime would cause the outer rim of the input gear to move at orders of magnitude beyond relativistic baseball[0].

[0] https://what-if.xkcd.com/1/

[tzs]

I have no idea how the physics of this works.

At first it seems pretty simple--but at that overall reduction a small motion at the motor end translates to a motion at the far end that is ridiculously smaller than the Planck length. The motor end is a simple classical physics system, but that thing is a quantum system on the far end.

I have no idea how to figure out what would actually happen if you let that run for long enough that the far end should have moved significantly according to classical physics.

[Akronymus]

It will move but in such a small range, that the wobble of the atoms is MUCH larger over a "short" amount of time, than the effective movement of the axle. So, at some point, the wobble would just shift slightly.

And tolerances exagerrate that by a LOT.

[omginternets]

Ha! I wonder (having no mechanical engineering background) ... is it possible to to drive e.g. a tank up a hill using a lego motor with a large enough gear ratio?

[jonahrd]

This channel is a treasure trove for answer to similar questions:

[1] Can lego break a steel axle?

[2] How much load can the smallest lego gear handle?

[3] Testing lego gear and pulley systems

[1] https://www.youtube.com/watch?v=jRn5waE0qfk

[2] https://www.youtube.com/watch?v=YjhOGoZ-bNI

[3] https://www.youtube.com/watch?v=bWgTRHH656Y

[layoutIfNeeded]

No, because the plastic gears connected to the drive wheel would snap under the immense torque.

[coinerone]

I want to turn the last Gear backwards to see how fast the first Gear is rotating.

[k_sze]

You probably won't be able to turn it at all with bare hands due to the sheer friction of the first few gear axles at the other end being amplified so much.

[amelius]

Are these original Lego parts?

[bonzini]

Yes, unless noted otherwise he only uses original parts.

For example, in one video he uses Lego-compatible steel axles.

[hoppla]

Wonder how much energy is required to turn Zeus around a turn.

[theqult]

what if you try to spin it the other way around ?

[doublesCs]

Now do Googolplex:1