Re: Shuttle lift-off questions

In article <e8o4sg$8qk_001@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx>, jmfbahciv@xxxxxxx writes:
In article <7awrg.29$45.1205@xxxxxxxxxxxxxxxxx>,
mmeron@xxxxxxxxxxxxxxxxxx wrote:
In article <e8lb1h$8qk_001@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx>,
jmfbahciv@xxxxxxx writes:
In article <rdbrg.26$45.1126@xxxxxxxxxxxxxxxxx>,
mmeron@xxxxxxxxxxxxxxxxxx wrote:
In article <e8iqo1$8qk_002@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx>,
jmfbahciv@xxxxxxx writes:
In article <zbSqg.9$45.821@xxxxxxxxxxxxxxxxx>,
mmeron@xxxxxxxxxxxxxxxxxx wrote:
In article <e8g9gt$8qk_001@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx>,
jmfbahciv@xxxxxxx writes:
In article <1152104183.822500.125410@xxxxxxxxxxxxxxxxxxxxxxxxxxxx>,
"Randy Poe" <poespam-trap@xxxxxxxxx> wrote:

jmfbahciv@xxxxxxx wrote:
Question 2: One of the reporters, who was talking about the
reason for one of the delays (cracks in the insulation) said
that the fuel tank expands when emptied and contracts when filled.
This is counterintuitive to me. If the reporter is correct,
why does this happen? I'm assuming that filling the tank
decreases inside pressure?

I can't find a definitive answer as to whether it expands or
contracts when fueled. I found some stuff that talks about
it "expanding and contracting" during fueling, other stuff
that says it expands when filled, and other stuff that
mentions cryogenic fuel (liquid hydrogen and oxygen)
that is replaced with warm air as it empties.

This means that the bleed valve has to be opened? I've never
thougth about how those things are filled and emptied in
terms of the plumbing. I know enough that I wouldn't want
to do that work (I'm a wimp) :-) Or am I wrong about the
plumbing, too?


Possibly it is that change of temperature that accounts
for what the reporter was saying.

When I freeze something it expands; but this is solids.

Other than very few exceptions, stuff contracts, *not* expands, on
cooling.

Yup,yup. That's my bug. I'm a stup but I did achieve honestly;
I can't recall playing with anything but water.

Yes, thought so.

You are very good at spotting the single-point failure.

That's a significant part of my job.

I know that. But you're very good at it; see below.


Food is water.

That is true. So, you didn't realize that the common stuff you play
with is exceptional.

Exactly. I'm still have trouble acclimating to this one :-).

I wonder what kinds of very, very basic assumptions we have
because our common element is an exception? I'm not sure
I can even detect a single hidden assumption.

That frozen stuff floats on top of liquid stuff, for once.

Really!? That's another hidden assumption. Very hidden.

Mind you, this point is very important. As ice is lighter than water
(an exception, as I said( means that bodies of water freeze "from the
top" in winter, remaining liquid underneath, unless they're quite
shallow. This allows living creatures to survive winter unharmed.

It sure would make a good scifi subject.

Yes, for sure.

Does this have anything to do with Ken's comment about
biology is all about surfaces? I'm still thinking about that one.

This one is more complex. But, in a nut shell, biology is about
structures in liquid.

[emoticon hitting head with light bulb that didn't work]

I did not consider this at all. Like I said, you are very good.

and stuff is happening on the surfaces of the
structures.

I was making such little headway thinking about Ken's statement,
that I had to stop. Then I started to try to define a surface
but was failing at that. Then life intervened and the
thought project was put on a back burner.


But it could've been a different liquid than water.

Mercury? Why would it have to be a compound?

Compounds have more interesting chemical properties, in general,
allowing for more complexity. Polarity of molecules and the like.
But I wouldn't go as far as to claim that it absolutely "has to" be
one thing or another. So far our data base about fundamental
chemistry of living creatures includes one entry. Not enough to make
definitive statements.

Mati Meron | "When you argue with a fool,
meron@xxxxxxxxxxxxxxxxx | chances are he is doing just the same"
.

Relevant Pages

  • Re: Shuttle lift-off questions
    ... that the fuel tank expands when emptied and contracts when filled. ... that is replaced with warm air as it empties. ... That frozen stuff floats on top of liquid stuff, ...
    (sci.physics)
  • Re: Shuttle lift-off questions
    ... that the fuel tank expands when emptied and contracts when filled. ... that is replaced with warm air as it empties. ... Other than very few exceptions, stuff contracts, *not* expands, on ...
    (sci.physics)
  • Re: Shuttle lift-off questions
    ... that the fuel tank expands when emptied and contracts when filled. ... that is replaced with warm air as it empties. ...
    (sci.physics)
  • Re: Shuttle lift-off questions
    ... that the fuel tank expands when emptied and contracts when filled. ... that is replaced with warm air as it empties. ...
    (sci.physics)
  • Re: Ping Black Dragon
    ... continued to expand after cooling/soldifying, ... Cerrobend 158 expands when it cools/solidifies. ... from a liquid to a solid. ...
    (alt.machines.cnc)
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