[Geysers] Benchtop geysers

[Paul Strasser]

Hi.

About ten years ago my daughter and I built a remarkably successful geyser
out of a 1000ml Erlenmeyer flask, a stout rubber stopper with a hole, and a
section of copper tubing that exactly fit the hole.

To the top was attached (via some sort of glue-stuff like epoxy that
withstood the temps) to a funnel that had a large diameter of about 5
inches.  To the top of this we got some sort of weird plumber's plaster and
built a slightly inclined circular collecting basin on a piece of thin board
- how we attached the board to the funnel I don't recall, probably some of
that plaster.  It was held upright by a large corrugated paper box of the
appropriate dimension.

The copper tubing (about 1/4" diameter, I believe) is what we used for
variations.  Here's how - we'd fill the flask with water to about 700 ml,
stick the stopper (with copper tubing already pushed through the hole), set
the flask on an electric heating element (cheap at Target, etc.) and turn on
the juice.  

What was cool was how even modest variations in the tube affected the
eruptions.  For instance, how far above the bottom of the flask do you have
the end of the tube?  It mattered a great deal.  Also, the best results were
with the tube bent into two complete 360 degree vertical rings before going
straight up.

The result was like Tardy.  It would take a while for the water to heat up,
but eventually you'd notice the water level dropping in the flask because
it's rising in the tube.  Then you'd see the water begin to rise in the
funnel, then drop, then rise (a la West Triplet).  Finally, when the water
poured out onto the "collecting basin" it would erupt.  The highest drops
were 8-12 inches. When the water was exhausted it would quickly suck back
down into the flask (draining back from the inclined collecting basin), only
to play again within a minute - with the water rising in the funnel, etc.
What stopped it was the loss of water via spray and steam, so we'd just add
50 ml or so every few eruptions.

One thing - there were inevitable leaks. We finally placed another piece of
cardboard just above the stopper and gently surrounded it with an old bath
towel.  After 30 minutes it was rather damp, but better that than drips from
steam and spray leaking onto the heating element.

It was fun.  

We have the data for the variations we tried, but they're in a box with a
lot of Linda's 4th grade stuff.  

Paul Strasser

-----Original Message-----
From: geysers-bounces at lists.wallawalla.edu
[mailto:geysers-bounces at lists.wallawalla.edu] On Behalf Of Davis, Brian L.
Sent: Monday, January 26, 2009 3:07 PM
To: geysers at lists.wallawalla.edu
Subject: [Geysers] Benchtop geysers

First, a brief introduction. I'm a 40 y.o. stay-at-home Dad in Indiana, who
also has a PhD in physics, and teaches physics, geology, and astronomy at a
local university here in Indiana (a state notably lacking in geothermal
activity :( ). I finally took my family out to Yellowstone in the summer of
'06, and tagged along behind a group of gazers (I had no idea they existed
at the time) on a wonderful day, finding the bunch at Grand, and after that
trailing them as they seemed to know what they were doing for a nice play
from Oblong.

If I hadn't been hooked prior to that, I certainly was after. Thank you all
for instilling the addiction in another person. I never spoke to any of
you... but just listening to your verbal "play" during the geyser play was
one of the best parts of a fantastic dawn-to-dusk day.

I'm coming out of lurking to ask opinions and additional information on
constructing a "benchtop" model. This started out as a daughter's science
fair experiment, but I realized I could end up doing a lot more with it
personally after the fair. Here's the best paper I've found on it:

http://www.fmf.uni-lj.si/~planinsic/articles/LasicArticle.PDF

Note that this is a *very* simple model, but still interesting from the
standpoint of educating folks. What I'm curious about is suggestions for
variation and other measurements. I'm planning on making several "models",
including a simple tube (as in the paper), a tube with a constriction
(possibly a variable one, using a piece of soft tubing pinched externally),
multiple paths or reservoirs, and probably a more realistic model of
refilling from a already warmed reservoir (instead of the water draining
back from the eruption directly into the plumbing). I would value any
suggestions, comments, or critical comments on this idea. Not the science
fair part - getting a model that erupts and has a single variable (like heat
input) would be more than sufficient for that.

Thoughts I've had are what allows multiple plays like Grand, as opposed to
single eruptions, or what it takes in terms of the plumbing system, heating
rate, and recharge structure to generate a steam phase, and what keeps it
from happening in others. Obviously some of these are going to be too
difficult to do on a benchtop (no deep plumbing, no high pressures), but the
idea is interesting to me.

Ideas? and thank you once again for waking up a flatlander several years ago
- I still watch the videos I took that day, and love the conversations on
this list.

-- 
Brian Davis
wanabe gazer in Indiana_______________________________________________
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