On Apr 11, 5:30*am, "
wrote:
On Apr 10, 12:34*pm, Robert Macy wrote:





On Apr 10, 7:39 am, "
wrote:

On Apr 10, 9:11 am, TimR wrote:

On Apr 9, 10:05 pm, Robert Macy wrote:

Wow, how about less opinion and more learning?

The distance of motion is always the SAME, as I said, it is the
FREQUENCY, or speed, of the precession that changes with the strength
of the field. The precession rate for the calcium ion is around 20Hz
in the earth's 50 uT field.

Obviously you do not understand what precession is, nor how to
calculate forces in a B field.

Another example of the precession of an ion is the hydrogen ion in
water. As a home project, take a two liter bottle of water, wrap

Proof positive you do not understand, because this is NOT an example
of precession.
*(It is simple inductance and can be calculated by Maxwell's
equations.)

At the very least, the experiment is poorly stated. *He
says to just measure the "kick back to the coil"? *Any
coil that is energized and then turned off will generate
a current, as you correctly point out. * No water filled
bottle required. * Now perhaps he means measure the
DIFFERENCE caused by the presence of the water bottle?
Which would raise more questions, like how
much of that difference is due to the hydrogen ions
versus any other effects, such as the magnetic
permeability of water versus air..... * And I'd be kind of
surprised if the suggested home experiment is going
to be able to capture/ quantify the difference. *Like what would
one use to measure this small energy DIFFERENCE
coming out of a *collapsing elecromagnetic field?

Doesn't sound like a home experiment to me.
And as you point out, if you just put 10 amps through
a coil of wire, when you turn it off, you're going to have
a substantial "kick back" with or without any water.

Do a search for
constructing "proton precession magnetometer"

Looked at your links. *And the construction of that device
involves building specific coils, pulse control circuitry, an
amplifier, etc.
Then we get into the data acquisition and control......

Comparing that to what you posted:

"As a home project, take a two liter bottle of water, wrap
several hundred turns of wire around it. Then run 10 amps
through the wire, shut off the current abruptly and monitor
what is 'kicked' back into the coil. "

If that's what it takes, then I'd say my initial reaction
that the actual experiment was poorly stated was right. Your
post left the impression that it was a simple, trivial experiment.
Apparently it can be done at home, but it takes a lot
more work and material than just wrapping some wire
around a water bottle.

I accept your criticism that I poorly stated - apologize. One
develops some bad habits over the years especially from flippantly
saying something [more accurately referring to something] that is
thought to be already understood. I forget that many people have not
been exposed to the mechanism supporting the PPM, or worked with the
circuit blocks that put together make up the 'simple' construction
required to build a PPM.

Regarding bieng a home project. SIMPLE is relative. I designed
ultrasonic echocardiography instrumentation - a non-invasive
instrument that looks inside the body using sound waves. Besides the
obvious complexity of the ultrasooud generation and reception, the
system required 5 microprocessors including a particularly difficult
architecture called bit-slice architecture for converting images in
real time. Now THAT was NOT simple.

If you are interested, you can make a PPM at home using farily
available items:
2 liter bottle filled with distilled water [a friend of mine who makes
this item using a different chamber for commercial sale, swears
alcohol is richer in hydrogen atoms - He also sells a magnetometer
that measures the earth's field to 12 digits!!! Watching that thing
operate is a treat. We stood out in an unpopulated area with the
instrument's digits blurred by changing as the reading updated. Most
significant digit was steady, next digit sometimes changed, next digit
'rattled' a bit, and so on until the LSD was a complete blur. While
watching the display, the pattern moved slightly up into the more
significant digits. When I pointed that out to him he simply pointed
to a bus driving by 2 blocks away that was deflecting the earth's
field causing our display pattern to change !!!]
wrap with 18-20 Awg
run 10 to 20 amps through the wire, shut off current and watch the
voltage at the wire terminals.
measure the voltage AFTER shutoff using your soundboard as data
acquisition - if it's a 24 bit system, you don't need a preamp - you
will need diode clamping to protect the input..

The standard decay voltage after shut off will contain a 'ripple'
riding on the voltage. Perform an FFT on the signal you accumulated
in your soundcard and you will clearly see a spike at some frequency
near 2kHz, if you're in the US. It will also show you 60, 120, 180,
240, etc from the AC mains.

The pulse circuit does not need to operate every second, you can make
it a simple one shot deal and still watch. Don't use a mechanical
switch, they don't shut off abruptly, taking several milliseconds, up
to 20 milliseconds and often have contact bounce - making and breaking
repeatedly as you shut off current. You will need a solid state switch
to turn off the current. Turning on can be as sloppy as you want, but
turning off has to be abrupt, and be a single event.

So yes, a little bit of work, but it is possible to make one.