With Teeth
May 17, 2020 4:49 PM Subscribe
Inspired by Daniel de Bruin's "universe's biggest gear reduction," the Brick Experiment Channel constructed a googol:1 gear reduction with LEGO.
Bonus: what happens if you turn de Bruin's gear assembly from the other end—Will It Hit Lightspeed?
Bonus: what happens if you turn de Bruin's gear assembly from the other end—Will It Hit Lightspeed?
Wake me when it turns over. Zzzzzzzzzz.....
posted by njohnson23 at 5:22 PM on May 17, 2020 [1 favorite]
posted by njohnson23 at 5:22 PM on May 17, 2020 [1 favorite]
I'm completely ready to believe the LEGO will all still be there turning after that much time.
LEGO will still exist when mankind has died out and the Earth is finally swallowed by the expanding Sun. Only then will it cease to be.
posted by hippybear at 5:44 PM on May 17, 2020 [1 favorite]
LEGO will still exist when mankind has died out and the Earth is finally swallowed by the expanding Sun. Only then will it cease to be.
posted by hippybear at 5:44 PM on May 17, 2020 [1 favorite]
The sun will be stopped from swallowing the earth when it steps on a LEGO.
posted by oddman at 6:22 PM on May 17, 2020 [11 favorites]
posted by oddman at 6:22 PM on May 17, 2020 [11 favorites]
Whenever I see what people are doing these days I'm embarrassed that I got all excited whenever I made a Lego car that had four matching tires.
posted by Gorgik at 6:57 PM on May 17, 2020 [21 favorites]
posted by Gorgik at 6:57 PM on May 17, 2020 [21 favorites]
This is a very cool construction but there's something about the extreme simplicity of the construction of the original that makes the result more mind-boggling.
posted by kenko at 7:27 PM on May 17, 2020 [4 favorites]
posted by kenko at 7:27 PM on May 17, 2020 [4 favorites]
"... then the first second of eternity will be over."
posted by Johnny Assay at 7:36 PM on May 17, 2020 [2 favorites]
posted by Johnny Assay at 7:36 PM on May 17, 2020 [2 favorites]
You've slowed down the rpm's by a googol, but you've also increased the torque on the the output shaft by a googol. Probably enough to, I don't know, spin the earth in the opposite direction or something (neglecting the strength of the lego output shaft).
posted by 445supermag at 8:42 PM on May 17, 2020 [2 favorites]
posted by 445supermag at 8:42 PM on May 17, 2020 [2 favorites]
Related: Machine with Concrete - a gear reduction where the output shaft is embedded in a concrete block.
posted by NoxAeternum at 9:03 PM on May 17, 2020 [4 favorites]
posted by NoxAeternum at 9:03 PM on May 17, 2020 [4 favorites]
I only spent one semester as a physics major, but it seems pretty intuitive to me: if you have to rotate the first gear a googol number of times to make the last gear turn once, then to turn the last gear once with your bare hand, you’re going to have to exert enough energy to turn the first gear one googol times. Right?
posted by ejs at 9:11 PM on May 17, 2020 [2 favorites]
posted by ejs at 9:11 PM on May 17, 2020 [2 favorites]
That's the most dynamic video of gears not turning that I've ever seen.
I'd guess the motor and gear train wouldn't survive the forces necessary to overcome its own friction. But it doesn't matter; you couldn't even take up the slack in half the gear train in the lifetime of the universe.
posted by Western Infidels at 9:30 PM on May 17, 2020 [1 favorite]
I'd guess the motor and gear train wouldn't survive the forces necessary to overcome its own friction. But it doesn't matter; you couldn't even take up the slack in half the gear train in the lifetime of the universe.
posted by Western Infidels at 9:30 PM on May 17, 2020 [1 favorite]
if you have to rotate the first gear a googol number of times to make the last gear turn once, then to turn the last gear once with your bare hand, you’re going to have to exert enough energy to turn the first gear one googol times. Right?
I think that's right but as a practical (ha!) matter I don't think worm gears work the other way around to any useful degree. You wouldn't expect to be able to drive the wrong end of even a single stage of worm gearing.
posted by Western Infidels at 9:34 PM on May 17, 2020 [2 favorites]
I think that's right but as a practical (ha!) matter I don't think worm gears work the other way around to any useful degree. You wouldn't expect to be able to drive the wrong end of even a single stage of worm gearing.
posted by Western Infidels at 9:34 PM on May 17, 2020 [2 favorites]
> That's the most dynamic video of gears not turning that I've ever seen.
Did you try changing the playback speed in youtube's little settings widget?
posted by sebastienbailard at 1:25 AM on May 18, 2020 [1 favorite]
Did you try changing the playback speed in youtube's little settings widget?
posted by sebastienbailard at 1:25 AM on May 18, 2020 [1 favorite]
Try 1.75x, 2x, or 10000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000x?
posted by sebastienbailard at 4:13 AM on May 18, 2020 [3 favorites]
posted by sebastienbailard at 4:13 AM on May 18, 2020 [3 favorites]
I only spent one semester as a physics major, but it seems pretty intuitive to me: if you have to rotate the first gear a googol number of times to make the last gear turn once, then to turn the last gear once with your bare hand, you’re going to have to exert enough energy to turn the first gear one googol times. Right?
Yeah, basically.
A longer lever would help.
Like a LOT longer.
posted by entropone at 5:35 AM on May 18, 2020 [2 favorites]
Yeah, basically.
A longer lever would help.
Like a LOT longer.
posted by entropone at 5:35 AM on May 18, 2020 [2 favorites]
LEGO will still exist when mankind has died out and the Earth is finally swallowed by the expanding Sun.
And we'll still somehow found a way to step on a stray brick at 5 a.m. in the morning.
posted by Fizz at 5:43 AM on May 18, 2020
And we'll still somehow found a way to step on a stray brick at 5 a.m. in the morning.
posted by Fizz at 5:43 AM on May 18, 2020
My thoughts while watching this were:
Where the hell did he get all the gear rigs, including the set up for planetary gears?
That little brushed DC motor is going to live a very short life, recalling the online magic 8 ball that had a spin mechanism built from Lego bricks in the late 90's IIRC - it's motor lasted only a few months of intermittent use.
How many miles of slack are there collectively in all the teeth that need to be taken up?
I started thinking about why you would bother building something like that wherein there will be no reasonably observable output in most of the project, then I recalled that I implemented a version of the Knight's Tour in 6502 assembly running on an Apple II in 1985 or so and let it run 24/7. It ran for about 3 weeks before a brown out locked up the machine. So there's that.
Related: lego torsion on a steel axle.
posted by plinth at 6:41 AM on May 18, 2020 [5 favorites]
Where the hell did he get all the gear rigs, including the set up for planetary gears?
That little brushed DC motor is going to live a very short life, recalling the online magic 8 ball that had a spin mechanism built from Lego bricks in the late 90's IIRC - it's motor lasted only a few months of intermittent use.
How many miles of slack are there collectively in all the teeth that need to be taken up?
I started thinking about why you would bother building something like that wherein there will be no reasonably observable output in most of the project, then I recalled that I implemented a version of the Knight's Tour in 6502 assembly running on an Apple II in 1985 or so and let it run 24/7. It ran for about 3 weeks before a brown out locked up the machine. So there's that.
Related: lego torsion on a steel axle.
posted by plinth at 6:41 AM on May 18, 2020 [5 favorites]
I have questions!!
1. How come the ratio is based on gear teeth, and not size of gear? I've been wondering about my bicycle and I'd love to learn more about ratios!
2. The first set up, that said that certain wheels spun at hour, minute, and second. That was just a guess, right? I ask because I've been trying to figure out how I can create my own 3-5 minute tea timer, and I thought a small motor with the right gears might do the trick - but I have none of the materials or know-how for how to make that.
posted by rebent at 6:49 AM on May 18, 2020
1. How come the ratio is based on gear teeth, and not size of gear? I've been wondering about my bicycle and I'd love to learn more about ratios!
2. The first set up, that said that certain wheels spun at hour, minute, and second. That was just a guess, right? I ask because I've been trying to figure out how I can create my own 3-5 minute tea timer, and I thought a small motor with the right gears might do the trick - but I have none of the materials or know-how for how to make that.
posted by rebent at 6:49 AM on May 18, 2020
How come the ratio is based on gear teeth, and not size of gear? I've been wondering about my bicycle and I'd love to learn more about ratios!
Well, the number of teeth is proportional to the size of the gear. Occasionally it's advantageous to imagine that a set of toothed gears are actually perfectly non-slipping rollers; the equivalent round roller for a particular gear is its pitch circle. Assuming properly mating gear teeth, the ratio of the pitch circles of two gears will be the same as the ratio of the teeth.
There are lots of nice intro to gears resources online; this one is not a bad starting point.
posted by Kadin2048 at 8:56 AM on May 18, 2020 [1 favorite]
Well, the number of teeth is proportional to the size of the gear. Occasionally it's advantageous to imagine that a set of toothed gears are actually perfectly non-slipping rollers; the equivalent round roller for a particular gear is its pitch circle. Assuming properly mating gear teeth, the ratio of the pitch circles of two gears will be the same as the ratio of the teeth.
There are lots of nice intro to gears resources online; this one is not a bad starting point.
posted by Kadin2048 at 8:56 AM on May 18, 2020 [1 favorite]
1. How come the ratio is based on gear teeth, and not size of gear? I've been wondering about my bicycle and I'd love to learn more about ratios!
So, the ratio of the input to the output determine how many turns of the input gear it takes to result in one turn of the output gear. If they're connected by something like a chain - or by directly meshing teeth - then gear teeth is directly related to the circumference of the gear.
Your bike has a chain with links that are each a half-inch long (pin to pin). So if your front chainring is 52 teeth, then it has a relevant circumference of 26 inches (measured at the valley of the teeth - where the chain's pins sit).
So if you were in the 52-tooth chainring and the 16-tooth cog, then one turn of the crank would result in 3.25 turns of the rear wheel - the ratio of 52 to 16.
posted by entropone at 8:59 AM on May 18, 2020
So, the ratio of the input to the output determine how many turns of the input gear it takes to result in one turn of the output gear. If they're connected by something like a chain - or by directly meshing teeth - then gear teeth is directly related to the circumference of the gear.
Your bike has a chain with links that are each a half-inch long (pin to pin). So if your front chainring is 52 teeth, then it has a relevant circumference of 26 inches (measured at the valley of the teeth - where the chain's pins sit).
So if you were in the 52-tooth chainring and the 16-tooth cog, then one turn of the crank would result in 3.25 turns of the rear wheel - the ratio of 52 to 16.
posted by entropone at 8:59 AM on May 18, 2020
"Right?"
Yeah. I find some of the comments in this and the previous thread a little puzzling. Fully as an abstraction, it's just simple math. Implemented, it's about the practical limits in the particulars of fabrication and material properties. The former is self-evident and uninteresting; the latter depends upon minutiae extremely remote from the ideal and therefore also uninteresting. How much force does it take to break a Lego gear tooth? Not that much.
The one interesting thing is to really consider the contrast of the ideal to the practical with regard to uncertainty: i.e., slack or manufacturing defects or whatever. The relationship of input to output has a corresponding increase of cumulative uncertainty. This machine isn't what it appears to be. This is a lesson applicable across many domains.
posted by Ivan Fyodorovich at 9:24 AM on May 18, 2020 [3 favorites]
Yeah. I find some of the comments in this and the previous thread a little puzzling. Fully as an abstraction, it's just simple math. Implemented, it's about the practical limits in the particulars of fabrication and material properties. The former is self-evident and uninteresting; the latter depends upon minutiae extremely remote from the ideal and therefore also uninteresting. How much force does it take to break a Lego gear tooth? Not that much.
The one interesting thing is to really consider the contrast of the ideal to the practical with regard to uncertainty: i.e., slack or manufacturing defects or whatever. The relationship of input to output has a corresponding increase of cumulative uncertainty. This machine isn't what it appears to be. This is a lesson applicable across many domains.
posted by Ivan Fyodorovich at 9:24 AM on May 18, 2020 [3 favorites]
I'm completely ready to believe the LEGO will all still be there turning after that much time.
And that's why we recycle our plastic.
posted by WizardOfDocs at 1:55 PM on May 18, 2020
And that's why we recycle our plastic.
posted by WizardOfDocs at 1:55 PM on May 18, 2020
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