Recent comments in /f/space

daikatana t1_j78f9ds wrote

Reply to How does water work in a closed container in space? by UnhappyLibrary2540

At 1 atmosphere of pressure water will boil at 100C and the boiling point goes up as pressure goes up. If you keep heating water in a confined space it won't boil as long as it remains contained. It would start making steam but the steam would make the pressure go up. As long as the container holds it will just get hotter and hotter, well in excess of 100C.

This is what happens in a pressure cooker. The pressure builds to about 2 atmosphere and the temperature of the water can climb above 100C, cooking your food faster. A pressure cooker is a very weak vessel, though, it doesn't take much to blow the lid off (don't do that). If you had a vessel with thick steel walls, like the boiler in a steam train, you can go much higher.

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SaulsAll t1_j78b80m wrote

Reply to How does water work in a closed container in space? by UnhappyLibrary2540

Your thought is in the right direction: raising temp without increasing volume is going to raise pressure. And a higher pressure is going to mean it take more heat for water to change phase from liquid to gas. The phase diagram for water is what is important here. I think though this might be a better question for r/askscience, especially when hypothesizing an unbreakable container or an unlimited amount of heat.

Edit: Looking at other charts, there seems to be a region called supercritical fluid

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ShyElf t1_j78azmb wrote

Reply to How does water work in a closed container in space? by UnhappyLibrary2540

No, you'd just get hot and high pressure water until it went supercritical and there was no longer a sharp gas/water phase transition. Also, the pressure would be rapidly huge, because you're not letting the water undergo thermal expansion. Also, it would do the same thing on Earth.

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triffid_hunter t1_j78asm8 wrote

Reply to How does water work in a closed container in space? by UnhappyLibrary2540

Steam engine boilers have been doing something similar for over a hundred years - boiling occurs when the partial pressure of a liquid exceeds ambient atmospheric pressure, so you can just jack up the pressure to force a hot liquid to not boil, and they kinda do this by themselves by simple thermal expansion in a filled closed volume.

From memory, steam engine boilers commonly operated at something like 300+°C to get sufficient working pressure for efficient operation, and there were numerous boiler explosion disasters before we worked out how to make them strong enough to withstand the insane pressure.

Conversely, if you reduce atmospheric pressure, water will boil at a lower temperature - and in fact there's heaps of videos on youtube where folk chuck a cup of water in a vacuum chamber and make it boil until it freezes from the evaporative temperature loss, and also explains why it's really difficult to make a decent cup of tea or coffee at high altitudes.

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okopchak t1_j78ahqo wrote

Reply to How does water work in a closed container in space? by UnhappyLibrary2540

The weirder behaviors for water generally crop up when it is allowed to move around or mixes with another liquid. A fully filled container of H2O that slowly gets heated will get hotter, the increase in temperature will increase the local pressure as the water expands. The higher pressure will raise the boiling point of water depending on the strength of your container it will either explode or may eventually achieve what is called a super critical state

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SpartanJack17 t1_j7637o6 wrote

Reply to Mars:The Lost Home by KainGreyson

Hello u/KainGreyson, your submission "Mars:The Lost Home" has been removed from r/space because:

  • Such questions should be asked in the "All space questions" thread stickied at the top of the sub.

Please read the rules in the sidebar and check r/space for duplicate submissions before posting. If you have any questions about this removal please message the r/space moderators. Thank you.

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SpartanJack17 t1_j7636i1 wrote

Reply to Mars:The Lost Home by KainGreyson

>What if Mount Olympus, and many other locations that we have only heard or read about actually existed?

Mount Olympus is a real mountain in Greece LMAO.

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