The vacuum compartment inside of a thermos would probably have atotal exposed area of about 1square ft. The amount of atmosphereic pressure on 1sq ft would be about 1000lbs! But when i looked inside of my thermous it apears to be just a relatively thin set of glass jars.
Why doesn't the atmosphere shatter it?
ALso, i saw on mythbusters that they have a big vaccum chamber and the clear door on it is about four inches thick! Why the difference?
2007-09-06 20:10:05 · 4 answers · asked by gentlest_theirsintheworld 2 in Science & Mathematics ➔ Physics
That's a good observation. First, a household thermos isn't a perfect vacuum. Second, it's structurally designed to handle the pressure. The pressure is steady and uniform.
You can get a clue about its structural strength when you take it apart to wash it. You can apply considerably more than 15 PSI pressure just by holding the vacuum bottle. That's more stress than the uniform pressure from the atmosphere because it's unequally distributed. If the bottle can handle that, it can handle the uniform pressure of the air.
The door you mention is probably larger and is probably not spherical.
2007-09-06 21:24:21 · answer #1 · answered by Frank N 7 · 0⤊ 0⤋
The point that is missing here is that atmospheric pressure has little part to play here because it is sealed inside when the cork is pushed in, it is to all extents, neutralized. The vacuum is a partial vacuum, heat loss is prevented by the highly mirrored inner liner of the thermos and the minumum contact areas made with the outer case.
2007-09-10 21:00:07 · answer #2 · answered by johnandeileen2000 7 · 0⤊ 0⤋
Uh....is there gonna be a test on this? Because I didn't study, my cat ate my homework, and I couldn't give a half-a-flying-nerd about the vacuum qualities of a freegin' thermos.
Thermos OK. If it breaks, it is not OK. Put in trash bin.
What in the hell are they trying to teach you in those schools now?
Thermos velocity, pressure, stress factors, and tendancy for insulative abilities?
How about anything to do with life? Nope. Gotta rate the thermos. It's a lot like rating the personality of Al Gore. Is he a vacuumous person? Does he make my decisions? For many of you, the answers to that would be, "yes".
You don't need to get lives. You already had them. Use them for something other than allowing idiots to cause yourselves to be focused upon really really stupid crap.
Hoo-Boy! Think for yourselves. Please!
Nad
2007-09-07 03:27:14 · answer #3 · answered by Anonymous · 0⤊ 1⤋
no matter what area the perfect vacuum will always be -1atm.
then you will based your design on this pressure. If a big door is not supported properly it will need a stronger material.
shape will also affect the design. vessels are design such that stresses are minimized or optimized.
2007-09-07 03:23:50 · answer #4 · answered by dbondocoy@yahoo.com 3 · 0⤊ 0⤋