# antique electrons

Discussion in 'Electronic Basics' started by Dan Jacobson, Apr 26, 2004.

1. ### Dan JacobsonGuest

If I connect an old silver dollar into a circuit, will I be
"exchanging electrons, many of which haven't left it since 1823"?
Hmm, if I usually kept it in a plastic mount, then I guess yes.
Hmmm, of course, OK, never mind.

Say, what is the electrical equivalent to putting some dye in water as
it flows thru a pipe? Water is the electrons, the pipe is the wire.

2. ### Garrett MaceGuest

Say, what is the electrical equivalent to putting some dye in water as

Not really surprisingly, there is a difference. Water can flow through a
pipe, dye can flow through a pipe: water can carry dye through a pipe. The
water itself is not being changed, it's just taking dye along for the ride.

Only electrons flow through a wire. They can't carry anything along with
them, at the same speed, to identify a particular group of electrons as they
pass through the wire. They also can't be modified or tagged for
identification purposes.

3. ### JeffMGuest

what is the electrical equivalent to putting some dye in water as
Modulating the electrical level with "information"
could be said to be similar to a dye "tracer".

4. ### Garrett MaceGuest

No, though electricity travels quickly through a wire, the electrons
themselves are moving very slowly through the wire. How fast depends on the
current level, but it's usually around a hundredth of a millimeter per
second. This isn't the actual speed of the electrons, this is the average
drift down the wire as they bounce around the atoms within the wire.

The original poster was wondering if there was a way to track specific
groups of electrons as they pass through a wire. Encoding information as
electricity only modifies the flow of electricity, not the medium or
carriers. It would be like conveying information through a water pipe by
varying the pressure, and not paying attention to any dye in the flow.

5. ### Watson A.Name - \Watt Sun, the Dark Remover\Guest

And since water is not compressible, the pressure would be transmitted
from one end of a long pipe to the other instantly. indicating the
'signal', but no flow would have occurred.

Seems to me that what he wants is something like an electrophoresis
system, where the ions would travel along the path of a gel as the
current passed thru it.

6. ### Tim AutonGuest

"Watson A.Name - \"Watt Sun, the Dark Remover\""
Water is compressible, just not very compressible, and nothing ever
moves instantly. Specifically, the pressure wave would travel at the
speed of sound in water (around 1500m/s).

Tim

7. ### Watson A.Name - \Watt Sun, the Dark Remover\Guest

Ok, real world, maybe simpler terms. And as you press on the column of
water at one end of a long pipe, it will come out on the other end, with
little delay. ;-) But the dye that you put in on one end will not come
out until the total volume of water has flowed thru. This was supposed
to be an analogy to the electrons in a wire, not a treatise on physics
of water flow.

8. ### Pieter HoebenGuest

You cannot see it that way. With water you have a large flow compared
to the amount of water in ther pipe. So to fill a bucket of 10 liters,
you put 1 leter in the pipe (assuming there was ait in it), and then
10 liters in the bucket. But when tere was already water in it, you
move 1 liter that was in the pipe into the bucket, and 8 new liters in
the bucket, and the pipe is filled with the last 1 liter.

A wire is like a filled, and extremely wide, pipe. To have large
currents, you only need relatively slow movement of electrons. I did
calculate that once in the past, but wouldnt know where to find the
results. Could be something like meters a year or so (if I remember
well.....).

Regards,

Pieter Hoeben
http://www.hoeben.com

9. ### John LarkinGuest

Yes. Only the valence electrons can be pushed around, of course. It
turns out that most electrons are quite old.

John