Brilliant!
As with many a scientific experiment, it was astute observation and an unexpected happenstance that provided valuable information.
The meter response before the hands were dunked was much looser than during. I can think of two reasons why this might be so: 1) cold hands and/or circulation cut off, 2) the meter was operating in a different range. That one can be corrected by placing a resistor in line with one of the leads to bring the meter back into range.
All in all, hands totally off cans with needle responding says to me that the sweat/unsweat argument is now laid to rest.
If you want to see if you can produce some blowdowns with hands off the cans, well, that would be heroic.
I just watched the underwater videos. Thanks for making them Paul, they were very interesting. I especially enjoyed the foot one. As a result of viewing them I can suggest another hypothesis to those which Ted advances for the observed difference in responses.
First a slight digression. Here are two prior posts, #17 & 18, which I consider relevant to the topic at hand. They constitute an electronic engineer & experienced auditor, a person well known among freezoners & an occasional poster on ESMB, friend's understanding of the function of the emeter and how it couples to the body's neural network.
http://www.forum.exscn.net/showthread.php?p=104779#post104779
Okay, given Roland's discussion, the most important areas to measure from are those rich in nerve ends tied directly tied to the brain structure. Among such parts of the body the fingers, palms, earlobes, toes, etc., are especially suitable.
Now in the mechanics of the experiment, the water in the buckets serves as a general aid to conductivity. Something like strapping a much larger electrode to the body part being measured. Because of the relatively high conductivity of the water it is not necessary to have direct contact between the skin and the electrode can. The water connects the whole of the submerged body part to the whole of the submerged electrode can.
However, now the can is not sensing electrical signals directly from those areas richest in nerve endings but it is measuring an averaged electrical signal from the entire submerged area of the body. This is so whether or not the body part remains in direct contact with the electrode can.
This suggests that improvements in "tone arm" reading may be as the result of more effective skin contact. Thus the "base level" of body conduction is more readily established and "tone arm" appears to drop.
However, the increased skin contact comes at the expense of greater averaging of total neural signals. The diminishment of reads as indicated by the need to increase sensitivity could relate to this "loss of signal" from the averaging of neural potentials over a greater area of the body and a resultant lesser effect of those areas rich in nerve endings.
Mark A. Baker