AC voltage from aluminum Grounded?

[THORPE]

My knowledge of AC voltage is very basic but I have a question.

I stumbled upon this by accident.

If you take a piece of aluminum, stick one one end into the ground just a little, say 1".

Then take a volt meter, stick one lead into the ground, the other lead anywhere on the aluminum above the ground, you get a small AC voltage reading.

It seems to have a higher reading with thicker aluminum than thin but it is a consistent reading with anywhere from .8 - 1.50 Volts AC.

Aybody know of this and what the source could be?

 

[Nik_2213]

Do you get a reading on DC ?? Do you get a reading when you put the alumini(u)m and probe into slightly salty water ? I suspect you've re-invented the electric cell...

 

[THORPE]

Haven't tried the Salty water but no reading on DC

 

[Dadface]

Hello THORPE I had the same thought as Nik but... no reading on D.C? Another thing that springs to mind is that the aluminium rod is acting like an aerial(antenna).The aluminium and its oxide layer at one of the connection points could be acting as a diode and with a meter to complete the circuit you have a simple crystal radio set.Again the problem is that there is no reading on D.C and the voltages you measure seems rather high(perhaps you could try high impedance headphones or a crystal earpiece in place of the meter).Well,I'm stumped but it's an interesting problem.