Foucault pendulum
en.wikipedia.org
Foucault pendulum
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Re: Foucault pendulum
#2> The pendulum was introduced in 1851 and was the first experiment to give simple, direct evidence of the earth's rotation.
The existence of the day-night cycle should have sufficed.
Re: Foucault pendulum
#3> The pendulum was introduced in 1851 and was the first experiment to give simple, direct evidence of the earth's rotation. The existence of the day-night cycle should have sufficed.
The pendulum shows you the net rotation of the pendulum about the Earth's axis of rotation, the rotation of the Earth about the Sun, the Sun about the center of the Milky Way, the Milky Way about the gravitational center of our local cluster, etc., etc.
Having not known, I think I would have strongly guessed that the rotation of the Earth about its own axis would be by far the dominant factor, but it's still good to measure.
Re: Foucault pendulum
#4> The pendulum was introduced in 1851 and was the first experiment to give simple, direct evidence of the earth's rotation. The existence of the day-night cycle should have sufficed.
That doesn’t tell you whether the earth rotates or the sun revolves around the earth.
Re: Foucault pendulum
#5> The pendulum was introduced in 1851 and was the first experiment to give simple, direct evidence of the earth's rotation. The existence of the day-night cycle should have sufficed.
In addition to sibling comments, we should note that not all observations are experiments. There is a distinct difference between experiment and mere observation: In an experiment, we are carrying out a repeatable recipe in order to try to falsify a hypothesis. We are not merely theory-crafting, working to explain what we see, but we are trying to disprove what we have theorized.
Re: Foucault pendulum
#6> The pendulum was introduced in 1851 and was the first experiment to give simple, direct evidence of the earth's rotation. The existence of the day-night cycle should have sufficed.
[deleted]
Re: Foucault pendulum
#7> The pendulum was introduced in 1851 and was the first experiment to give simple, direct evidence of the earth's rotation. The existence of the day-night cycle should have sufficed.
That doesn’t tell you whether the earth rotates or the sun revolves around the earth.
Yes. People have been taught that the earth revolves around the sun, and sometimes we use it as a way to be smug about how much smarter we are than the ancients. But schools do a huge disservice to students by not showing them that there's not in fact any way to know this from the information the ancients had available to them. About all you can infer from the way the sun changes position in the sky is that some kind of movement is happening. Because the earth feels solid under your feet you might assume that only the sun, planets, and stars are moving. This is valid according to Occam's Razor.
Indeed for hundreds of years western astronomers predicted the locations of the planets using epicycles and not by calculating orbits assuming a heliocentric system. And it worked! Beautifully! The earth-centric model has excellent predictive power. It explained everything the ancients were aware of.
This is all as a lesson in both humility and in recognizing that our ancestors were not stupid or lacking reason. They just didn't have the tools we have. And for all that the heliocentric seems obvious, remember that it is only obvious because we have been taught it. Our ancestors had been taught an earth-centric model instead, and it was obvious to them.
Re: Foucault pendulum
#8> The pendulum was introduced in 1851 and was the first experiment to give simple, direct evidence of the earth's rotation. The existence of the day-night cycle should have sufficed.
In addition to sibling comments, we should note that not all observations are experiments. There is a distinct difference between experiment and mere observation: In an experiment, we are carrying out a repeatable recipe in order to try to falsify a hypothesis. We are not merely theory-crafting, working to explain what we see, but we are trying to disprove what we have theorized.
And to clarify, observation is as important as experiment, because observation gives us new ideas for experiments. Collecting anecdotes and making observations is as important as designing experiments. You can't really be a scientist if you don't pay attention to the natural world.
Re: Foucault pendulum
#9Earlier quoted context omitted.
That doesn’t tell you whether the earth rotates or the sun revolves around the earth.
Yes. People have been taught that the earth revolves around the sun, and sometimes we use it as a way to be smug about how much smarter we are than the ancients. But schools do a huge disservice to students by not showing them that there's not in fact any way to know this from the information the ancients had available to them. About all you can infer from the way the sun changes position in the sky is that some kind…
To turn that on its head, it's a wonderful teaching moment to ask a room full of smart students to try and prove (or even convincingly argue) that the Earth moves around the sun. A great way to get people to examine their assumptions and look afresh at the world around them.
As you say, it is indeed very hard to do, which is a good part of the reason why even when Copernicus published his heliocentric model (not a proof, but a new mathematical model) his ideas took decades to become mainstream. If you have a rudimentary telescope / binoculars and know to look, then you can observe that Venus has phases and use that as a basis for argument (as Galileo did), but even then, it's perfectly possible to cook up special models where Venus has phases and the earth is still stationary (see https://en.m.wikipedia.org/wiki/Tychonic_system).
Re: Foucault pendulum
#10Earlier quoted context omitted.
That doesn’t tell you whether the earth rotates or the sun revolves around the earth.
Yes. People have been taught that the earth revolves around the sun, and sometimes we use it as a way to be smug about how much smarter we are than the ancients. But schools do a huge disservice to students by not showing them that there's not in fact any way to know this from the information the ancients had available to them. About all you can infer from the way the sun changes position in the sky is that some kind…
They certainly could and in fact did.
https://en.wikipedia.org/wiki/Heliocentrism#Aristarchus_of_S...