Timeline for Inaccuracy at measuring gravity constant with Cavendish experiment
Current License: CC BY-SA 3.0
7 events
| when toggle format | what | by | license | comment | |
|---|---|---|---|---|---|
| Apr 4, 2020 at 21:45 | vote | accept | BlobbyBob | ||
| Oct 4, 2015 at 13:35 | comment | added | Floris | @BlobbyBob there are many possible sources of drift in an experiment like this - including the torsion wire itself which can "unwind". It is imperative that you eliminate air currents and effects of static electricity, and that you observe the drift in the setup over many cycles - preferably automatically. A web cam looking at the reflection of a laser pointer produces an image that can be trivially analyzed to give you the deflection curve over many days. | |
| Oct 4, 2015 at 5:07 | comment | added | BlobbyBob | @Floris Because I'm only on weekends in the house where I built up this experiment the pendulum had 5 days to stop rotating. After putting the large spheres in place I waited about 90 mins before measured. Is this enough or should I wait much longer? | |
| Oct 4, 2015 at 3:37 | comment | added | WhatRoughBeast | Air currents don't necessarily settle. | |
| Oct 4, 2015 at 2:30 | comment | added | Floris | @WhatRoughBeast quite possible. It is a hard experiment. Looking at the motion over time will show if there is drift (charge would leak, air currents would settle) or a constant offset. Only the latter can be gravitational. | |
| Oct 4, 2015 at 2:29 | comment | added | WhatRoughBeast | Another, obvious, possibility is that in moving one or both of the large spheres into place a static charge is being induced, which will overshadow the gravitational effects. | |
| Oct 3, 2015 at 19:04 | history | answered | Floris | CC BY-SA 3.0 |