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37 votes
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How dense of an atmosphere do I need to "float" an ocean of liquid at 1000 ft elevation?

There are several pairs of liquids and gasses where the gas is more dense, and thus the liquid will float on it... for a while at least, as in many cases one will dissolve into the other, which ruins ...
Logan R. Kearsley's user avatar
33 votes

What would realistically happen if you could water walk?

It will be WAY harder than it sounds Not sure if you've ever seen these floating lilly pads at any public pools, but they work more or less as described. The below body of water is completly still, ...
Nosajimiki's user avatar
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28 votes
Accepted

How to create a floating rock

Concrete pontoons I'd give you a link but since it's a standard product they're all commercial sites. They float. They're rock-like, you can sculpt what you like into the top or just stick a layer of ...
Separatrix's user avatar
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17 votes

How to create a floating rock

Pumice rafts are already thing. Typically created by volcanic eruptions, they can be gigantic -- one off New Zealand in August 2012 was reportedly 480 kilometres (300 mi) long and about 50 ...
David Hambling's user avatar
16 votes

What would realistically happen if you could water walk?

Fall over in most cases Lets get a few assumptions out of the way. I'm assuming it'll be like standing on glass. With the right shoes or bare feet you have purchase on the surface. It'll not be like ...
Trioxidane's user avatar
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9 votes

How to safely construct deep underground harbors on a Snowball Earth?

Physics Question: I do not think the pressure underwater changes when the surface freezes. Pressure is created by weight, and freezing does not change weight. You could say that liquid gases of former ...
Bald Bear's user avatar
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9 votes

How dense of an atmosphere do I need to "float" an ocean of liquid at 1000 ft elevation?

Let me build on @AlexP's comment, because he's completely right. You can't have liquid water floating above any atmosphere no matter the pressure because LOX is lighter than water. The water would ...
JBH's user avatar
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9 votes

How to create a floating rock

Expanded clay aggregate already exists and used in construction. It looks pretty much like pebbles, and its density can be as low as 1/4 of that of the water.
Alexander's user avatar
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7 votes

What effect would water that is twice as dense, while still liquid, have if a human were to try and swim in it?

Use the Dead Sea as a reference I would suggest learning more about what it's like to swim in the Dead Sea. Thanks to its salt content, the water there is 25% more dense than fresh water. Even though ...
Rob Watts's user avatar
  • 20k
6 votes

How dense of an atmosphere do I need to "float" an ocean of liquid at 1000 ft elevation?

Water is slightly diamagnetic, which means it will repel a magnetic field of either polarity. One well known example of this is the levitating frog experiment, which used a 16 tesla magnetic field: ...
jpa's user avatar
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4 votes

Deities vs You /Liquid Anon/ What'd be the most optimal carrier fluid comopsition?

Your nanites are the fluid. https://www.amazon.com/Imagine-If-Hematite-Magnetic-Gorgeous/dp/B01FE2GI7W They are faceted, and can lock together on their facets. They can roll across each other and ...
Willk's user avatar
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4 votes
Accepted

Aerodynamics of propeller vs screw/fin based aerial propulsion

Unlikely The principle of screws as propulsion works as good as it does in water, because water is non compressable, meaning the screw can't not press the medium outwards. With air however you loose ...
OneSaltyAceTanker's user avatar
4 votes

What effect would water that is twice as dense, while still liquid, have if a human were to try and swim in it?

More of a physics question than worldbuilding question really, but you would have twice the buoyancy with twice the pressure at the same depth as regular water, and twice the force/drag/lift. Water at ...
DKNguyen's user avatar
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4 votes

What would realistically happen if you could water walk?

The answer, as often is the case with magic, is: whatever the spell creator managed to instill in the spell. In other words, what happens is entirely dependent on how the spell works... and there are ...
Corey's user avatar
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4 votes

How quickly will the oceans freeze if Earth becomes a rogue planet?

The USGS estimates 10,633,450 km³ of water on earth (i'll call that 1e19 kg. i am going to go ahead and assign that a temperature of 10°C. With, roughly, energy of freezing 333kJ/kg and heat-capacity ...
bukwyrm's user avatar
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3 votes
Accepted

Could a fish lie horizontally with an air-space in its head?

Yes, it can. As long as the head where the air inflated organ is located has also a corresponding "ballast organ" which can be made heavier on demand, to compensate for the positive buoyancy ...
L.Dutch's user avatar
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3 votes

What would a fish look like if it was adapted to live in honey?

It would need 3 things: It would need to have a very large strength to size ratio to push it through honey to push through the high viscosity substance. It would need to breath air because honey does ...
ShadoCat's user avatar
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3 votes

How to create a floating rock

As long as it displaces more water than it's own weight it'll float. Concrete barges and rafts exist already.
LazyReader's user avatar
3 votes
Accepted

How to safely construct deep underground harbors on a Snowball Earth?

Physics question Converting the sea/atmosphere to different states of matter will not affect their mass or the pressure they exert. So the pressure at 1km below the surface would remain roughly the ...
Slarty's user avatar
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3 votes

How dense of an atmosphere do I need to "float" an ocean of liquid at 1000 ft elevation?

Liquid over gas seems like it's a pretty hard slog. Gas over gas: The densest gas I can find is per-fluoro-butane C4F10 with a molecular weight of 238, so at stand temp and pressure it's about 7 ...
Sherwood Botsford's user avatar
2 votes

Diffusion and Organic Reactions in Mist

Yes. This could happen. Considering your scenario but with volatile alkanes instead of lipids. I could imagine the sun coming up and water evaporates. Mist forms. As it gets warmer, it is warm ...
Willk's user avatar
  • 305k
2 votes

How dense of an atmosphere do I need to "float" an ocean of liquid at 1000 ft elevation?

I'll answer the second part of this question because yes, there are absolutely easier ways to do this than with a floating ocean. The phenomenon that causes that mirror-like effect is Total Internal ...
Dubukay's user avatar
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2 votes

What would realistically happen if you could water walk?

If waterstrider physics are anything to go by, they'll be paddling their way around on their bellies. Also disturbing the water surface too much might be considered murder. I feel like you saw the ...
ProjectApex's user avatar
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2 votes
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What would a fish look like if it was adapted to live in honey?

Ichthys thixotropicus A very strange species of fish, native, and indeed endemic, to New Zealand, is the Ichthys thixotropicus. It was first described by William Wigglesmore in the early 19th century. ...
elemtilas's user avatar
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2 votes
Accepted

Which limbs should be retained or lost to turn this land animal into a swimmer?

Convergent evolution Take a look at this picture from https://cannonballread.com/2018/03/to-the-reference-shelf-with-you/ The common pattern is a smooth elongated body with a pointy tip. Three (...
Menno van Lavieren's user avatar
1 vote

How would hydrostatic skeletons respond to different atmospheric pressures?

The "hydrostatic skeleton" idea basically revolves around using incompressible fluids (usually water) to maintain a structure, like in big trees or hemichordates. In fact, as silly as it ...
controlgroup's user avatar
  • 5,375
1 vote

Melusine/Two-tailed Merfolk’s Dual Mobility, Land and Sea

All you're describing is a basically a scuba diver. Sub par in the water compared to aquatic animals and ok on land. Both a fin on each leg and a single one for both are used already by divers. A mono ...
Kilisi's user avatar
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1 vote

How quickly will the oceans freeze if Earth becomes a rogue planet?

Oh boi, what a question. Since I am an oceanographer, this is more about what the process of freezing would potentially look like To start, the oceans will not completely freeze. Rather the pure water ...
Lilly Whelan's user avatar
1 vote

What would realistically happen if you could water walk?

It's probably easier to just take a boat. If the effect is equivalent to increasing surface tension, then in still weather it should be similar to walking on very smooth (and slippery) ice. Although ...
Withadel's user avatar
  • 717
1 vote

What would realistically happen if you could water walk?

It would be like walking during an earthquake There's rarely such a thing as "still water." It looks still, but it's moving. The wind moves it, the earth moves it, temperature changes move ...
JBH's user avatar
  • 126k

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