4 ms·
Oh so the earth density is merely the motivation for the experiment? I read it as the earth mass actually being used somewhere in the formulas within the setup
by alkonaut 6mo ago
Oh so the earth density is merely the motivation for the experiment? I read it as the earth mass actually being used somewhere in the formulas within the setup itself which was what confused me.
He uses his experiment to calculate G based only on the test masses and spring and then the _result_ of the calculation was just used as a final step to calculate the mass of the earth, and then from that the density?
- ricksunny 6mo agoSeveral years back when I first learned about the Cavendish experiment, I was indeed surprised that he was able to measure anything related to gravity without using a planetary-scale mass as one of experimental masses.
- recursivecaveat 6mo agoClever experiments to measure tiny values are probably my favorite kind of science. Millikan found the charge of an electron by looking for a common integer multiple of charge in tiny oil droplets. Or LIGO measures gravitational waves by watching the interference pattern generated over time by two light beams taking different paths.
- ricksunny 6mo agoY’know, I went and looked at the current Wikipedia page for the Cavendish experiment. There’s apparently more nuance than my simple outline offers, particularly as G wasn’t treated as an isolated quantity till decades after his experiment. Linking directly to section anchor: https://en.wikipedia.org/wiki/Cavendish_experiment#Reformulation_of_Cavendish's_result_to_G https://en.wikipedia.org/wiki/Cavendish_experiment#Reformula... There is less description than I would like, but I am happy to have been made aware of the discrepancy at all.