well here is the physicist answer.....not quite what i had hoped
<table cellpadding="0" cellspacing="0"><t><tr><th>Expert: </th><td>Expert</td></tr>
<tr><th>Subject: </th><td>What is the underlying 'force'</td></tr>
<tr><th>Question: </th><td>Hello,
I am greatly please to see a website such as this. I am a wine maker
and today noted that my hydrometer when placed into my fermenting must
would "travel" from the center area of the 150 liter open top tub and
move towards the fermenting tub walls. I am using larger diameter tubs
than i used to and i am leaving the hydrometer in longer to get true
must temperatures and this explains why I had not seen this phenomenon
before. Is this a molecule compression difference between the center
and of the wine molecules at the walls? Why wouldnt the hydrometer stay
in the 'perfect' center if placed there?
Thank you - AL</td></tr>
<tr ="answer"><th>Answer: </th><td>Please
forgive my delay in responding -- it's the only way I can think of, to
ensure I am not assisting with academic work, of which homework is just
a small part. Also, as I can not determine the veracity of what people
post, I can not know whether or not a question involves academic work.
Anyway, despite checking out
www.grapestompers.com/articles/hydrometer_use.htm</span>
http://winemaking.jackkeller.net/hydrom.asp
I
am unable to determine why your hydrometer would drift to the side,
particularly since you are using a larger tub. PERHAPS there is a
density or temperature difference between the center and sides, one
that did not appear before in your smaller vats -- but a difference so
large as to move a hydrometer would not last long in a liquid. The
surface tension "bubble" at the top of a fluid that MIGHT cause
something to drift to the side
http://tinyurl.com/WarpedFluidPic
would not be a significant factor in this large a container.
When
I first glanced at this question, I thought it would be easy to
explain. I was wrong -- I just don't know enough about the situation to
make an intelligent guess on what's happening. Sorry.</td></tr></t></table>