dave9000's comments

On: Bending Spacetime in the Basement (1997)

[dave9000]

A caveat. I had the change to perform a similar experiment at work testing very sensitive accelerometers. Believe it or not, the biggest source of errors was the bending of the floor due to the test masses! A better setup would be to suspend the spheres exactly like the tuna cans, and test two configurations rotated by 90 degrees.

[lisper → dave9000]

Huh? Why would the bending of the floor matter?

[dave9000 → lisper]

For the accelerometers the problem was the tiny tilting of the sensitive axis in the gravity field. In this case you're probably right that this doesn't matter - but in general it is difficult to rule out every second-order effect when the forces at play are so small with respect to g.

[SamBam → lisper]

I assume if your weights are resting on the floor, and the pivot point of the swing arm is resting on the floor, then the floor deflecting may cause the arm to swing even in the absence of an attraction to the weights.

[lisper → SamBam]

> the pivot point of the swing arm is resting on the floor

But it isn't. It's suspended from a support by a thin filament. That's the whole point of the experiment.

[layer8 → lisper]

It’s suspended from an aluminum ladder standing on the floor.

[lisper → layer8]

That's true, but the details of the placement of the ladder doesn't matter at all. The only thing that matters is that the ladder doesn't move or wobble around during the experiment.