Guitar lead tip(hot) and sleeve(ground) query

[ourclarioncall]

After doing some experimenting tonight I realised I could touch the wires from my single coil pickup directly onto the tip and sleeve of the guitar cable plugged into my amp and it would work and I would hear the signal going through

ThenI started touching the guitar cable with my fingers. I noticed 3 different possible sounds from

A. touching the sleeve
B. touching the tip
C. touching both sleeve and tip at the same time

What is going on here and why the different noises?

I think A created silence or the amp went quieter. B was loud buzzing and C was a quieter than B but still noisy

[JohnH]

You have literally 'touched' on a subject where, after trying the kind of things that you have and noticed the results, most people get a sense of what happens and what to expect from touching those connections, or grounding them so that they are not floating. But it's really hard to explain it properly, or understand it rigorously.

Im quite sure that an amp on a space station would behave in exactly the same way, even though it's thousands of miles above 'Ground' and Far Above the World.

That's why we need Ground Control, to ensure that our inputs are not Mysteriously Floating, which may indicate that our Circuit is Dead or rhar our amp sounds like bees in a Tin Can. In that case there's Nothing we Can Do (except maybe take a Protein Pill, and play some Earth-y Blue-s)

BTW, if anyone wants to know, I wear shirts from K-Mart.