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Analog tide-predicting machines are fascinating. The tide height is a function of the earth/sun/moon systems. Earth and Moon aren't at a fixed distance from ea
by jvm___ 3y ago
Analog tide-predicting machines are fascinating.
The tide height is a function of the earth/sun/moon systems. Earth and Moon aren't at a fixed distance from eachother, and neither is the sun, so every day is a unique tide but you can predict the range.
The analog way to do it is to make a gear for each point of data in the system and synchronize all their gears. Then you use them all to rotate one final gear, which will show you the prediction for the time you've chosen.
- calamari4065 3y agoI think this is a great example. It's pretty easy to mentally connect the orbit of a planet with the ratio of gears. Once you really understand how these systems are an analog of a physical problem, everything makes so much more sense
- jodrellblank 3y agoI used to know nothing about Lord Kelvin except he said things like "It seems, therefore, on the whole most probable that the sun has not illuminated the earth for 100,000,000 years, and almost certain that he has not done so for 500,000,000 years"[1] and allegedly "everything which can be discovered, has been discovered"; until last year's Veritasium video on YouTube[2] about analog computers, and learned he invented tide-predicting analog computers to "substitute brass for brains" and add sinusoidal curves, and a mechanical integrator to separate out individual sinusoidal frequencies from the sum. [1] https://zapatopi.net/kelvin/papers/on_the_age_of_the_suns_heat.html https://zapatopi.net/kelvin/papers/on_the_age_of_the_suns_he... [2] https://www.youtube.com/watch?v=IgF3OX8nT0w https://www.youtube.com/watch?v=IgF3OX8nT0w from about 3 minutes.