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Flat Earth Projects / Attempting to actually measure gravity
« on: March 06, 2019, 02:25:07 AM »
So since my previous experiment, while apparently detecting gravity type forces, did not yield a meaningful measurement of those forces:
It was close enough to the value of gravity that my rinky dink experiment may have caused that much error, but far enough that it wasn't even close.
So I've begun efforts to actually measure it. I'm intending to get a measurement accurate enough to either match theoretical gravity, or rule it out.
My setup is a roughly 70 gram tungsten weight suspended from two strings with a small fragment of mirror attached. The weight is hanging in water to slow down the swinging.
Then a laser interferometer setup bounces 532nm laser light off the mirror on the weight and the fixed reference mirror and the combined beams hit some white paper to form an interference pattern.
Theoretically, I will be able to measure movement of the weight in increments of half of 532nm since moving the weight 1nm increases the distance by 2nm.
And depending on how far the interference bands move I may be able to even guesstimate to the nearest quarter of 532nm.
It's still taking forever to settle.
Shown first is a test setup with a red laser.
Second, I'm showing it actually set up and "operating" with green laser, except it's still swinging too much, but the interference pattern shows up briefly at each end of the swing as the velocity briefly hits zero.
Sorry about the poor focus, my phone does not like focusing on green laser light. It's probably looking for face colors to focus on, and green is not that.
Third is showing the interference patterns as the weight still swings after an hour (while swinging in a cup of water.)
(The interference pattern is actually still there, but moving so fast it's a blur)
I could actually set up a pair of photo diodes at 90 degrees phase difference and track the quadrature and measure the swinging in realtime, but that's too much work to do before going out to dinner with friends.
Looks like this thing may never settle down completely, and even if it does, when I walk around to move the big weight nearby, the floor moves and the pattern goes crazy.
I guess 532nm isn't a very big distance.
It was close enough to the value of gravity that my rinky dink experiment may have caused that much error, but far enough that it wasn't even close.
So I've begun efforts to actually measure it. I'm intending to get a measurement accurate enough to either match theoretical gravity, or rule it out.
My setup is a roughly 70 gram tungsten weight suspended from two strings with a small fragment of mirror attached. The weight is hanging in water to slow down the swinging.
Then a laser interferometer setup bounces 532nm laser light off the mirror on the weight and the fixed reference mirror and the combined beams hit some white paper to form an interference pattern.
Theoretically, I will be able to measure movement of the weight in increments of half of 532nm since moving the weight 1nm increases the distance by 2nm.
And depending on how far the interference bands move I may be able to even guesstimate to the nearest quarter of 532nm.
It's still taking forever to settle.
Shown first is a test setup with a red laser.
Second, I'm showing it actually set up and "operating" with green laser, except it's still swinging too much, but the interference pattern shows up briefly at each end of the swing as the velocity briefly hits zero.
Sorry about the poor focus, my phone does not like focusing on green laser light. It's probably looking for face colors to focus on, and green is not that.
Third is showing the interference patterns as the weight still swings after an hour (while swinging in a cup of water.)
(The interference pattern is actually still there, but moving so fast it's a blur)
I could actually set up a pair of photo diodes at 90 degrees phase difference and track the quadrature and measure the swinging in realtime, but that's too much work to do before going out to dinner with friends.
Looks like this thing may never settle down completely, and even if it does, when I walk around to move the big weight nearby, the floor moves and the pattern goes crazy.
I guess 532nm isn't a very big distance.