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Water compresses under a high gradient electric field

phys.org

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Re: Water compresses under a high gradient electric field

#31

Post by wallace_f »

felipemnoa wrote: post #23
leovailati wrote: post #22

Earlier quoted context omitted.

I found it counterintuitive that it was predicted in simulation and then confirmed with experiments, rather than the other way around.

This is how lots of new science is discovered. One example is the Theory of Relativity. Sure it was not a software simulation per se but it was still simulated on paper. It was not confirmed by experiment until several years latter.

If I'm not mistaken I think what OP is referring to is an apparent emergent phenomena that contradicted theory, whereas I believe GR was discovered through theory (ie Einstein's "happiest thought" was in an elevator shaft).

Re: Water compresses under a high gradient electric field

#32

Post by akeck »

leovailati wrote: post #22
ahelwer wrote: post #2

"This is an unexpected phenomenon, contrary to what we thought we knew about nanopore transport. It took three years to work out what it was the simulations were showing us. After exploring many potential solutions, the breakthrough came when we realized that we should not assume water is incompressible. Now that we understand what's happening in the computer simulations, we are able to reproduce this phenomenon in t…

I found it counterintuitive that it was predicted in simulation and then confirmed with experiments, rather than the other way around.

It’s nice way to do engineering as well - Fully modeling every aspect of a collision first is often cheaper than doing multiple crash tests.

Re: Water compresses under a high gradient electric field

#33

Post by andromeduck »

A_Person wrote: post #28

It's always surprised me how many people do not know that water is incompressible! For example, when someone is filling a scuba tank, it's common to put the tank in a large, often metal-sided container of water. When asked why, the shop staff member will typically say: "In the unlikely event of the tank blowing up, the water will absorb the force of the explosion." But in fact, water being incompressible, it will abs…

That's just wrong. The the blast from the tank would have to displace water before of the energy of the blast can exit the side or top of the container. That spreads out the energy from the blast and the container would redirect much of that energy upwards both of which reduces the effective radius of the blast.

Re: Water compresses under a high gradient electric field

#34

Post by Arbalest »

inetknght wrote: post #3

This page, or something it loads, is causing Firefox to use 100% CPU. Cryptocurrency malware, perhaps?

Even with ublock origin+umatrix, so not many scripts were run. I was wondering whether that causes a script to fail and loop infinitely. IDK what conditions you guys were running your browser as.

Re: Water compresses under a high gradient electric field

#35

Post by Animats »

leovailati wrote: post #22
ahelwer wrote: post #2

"This is an unexpected phenomenon, contrary to what we thought we knew about nanopore transport. It took three years to work out what it was the simulations were showing us. After exploring many potential solutions, the breakthrough came when we realized that we should not assume water is incompressible. Now that we understand what's happening in the computer simulations, we are able to reproduce this phenomenon in t…

I found it counterintuitive that it was predicted in simulation and then confirmed with experiments, rather than the other way around.

Years ago, one of the HP people involved with early ink-jet printers told me that intuition about fluid behavior totally fails at that scale, and they had to use computational fluid dynamics to figure out how to get ink droplets to behave.

Re: Water compresses under a high gradient electric field

#36

Post by zamalek »

andromeduck wrote: post #33
A_Person wrote: post #28

It's always surprised me how many people do not know that water is incompressible! For example, when someone is filling a scuba tank, it's common to put the tank in a large, often metal-sided container of water. When asked why, the shop staff member will typically say: "In the unlikely event of the tank blowing up, the water will absorb the force of the explosion." But in fact, water being incompressible, it will abs…

That's just wrong. The the blast from the tank would have to displace water before of the energy of the blast can exit the side or top of the container. That spreads out the energy from the blast and the container would redirect much of that energy upwards both of which reduces the effective radius of the blast.

The shopkeeper is still somewhat wrong though: it's redirecting the energy, not absorbing it.

Regardless, Mark Rober and The Backyard Scientist have a pretty great video demonstrating exactly what is going on here: https://youtu.be/W4DnuQOtA8E

Re: Water compresses under a high gradient electric field

#37

Post by A_Person »

andromeduck wrote: post #33
A_Person wrote: post #28

It's always surprised me how many people do not know that water is incompressible! For example, when someone is filling a scuba tank, it's common to put the tank in a large, often metal-sided container of water. When asked why, the shop staff member will typically say: "In the unlikely event of the tank blowing up, the water will absorb the force of the explosion." But in fact, water being incompressible, it will abs…

That's just wrong. The the blast from the tank would have to displace water before of the energy of the blast can exit the side or top of the container. That spreads out the energy from the blast and the container would redirect much of that energy upwards both of which reduces the effective radius of the blast.

I'm no scientist and you may well be right. But I'm skeptical of your statement that "much" of the blast would be directed upwards. If you look at the pictures of tank explosions, they often show the entire room flattened right to floor level - not a big hole in the roof and minor damage everywhere else.

Re: Water compresses under a high gradient electric field

#39

Post by craftyguy »

yosito wrote: post #38

What would happen if you compress water using this method and then seal the container it's in and turn off the electricity? Anything interesting? Does the water stay compressed? Does the container explode? Does it depend on the strength of the container?

Intuition says that the water would then exert more pressure on the container. Like if you emptied and sealed a plastic bottle while at sea level, and then ascended to a high altitude in an airplane (or climb a mountain). The bottle would be bloated. Whether or not it would explode depends entirely on the properties of the container..

Re: Water compresses under a high gradient electric field

#40

Post by craftyguy »

A_Person wrote: post #28

It's always surprised me how many people do not know that water is incompressible! For example, when someone is filling a scuba tank, it's common to put the tank in a large, often metal-sided container of water. When asked why, the shop staff member will typically say: "In the unlikely event of the tank blowing up, the water will absorb the force of the explosion." But in fact, water being incompressible, it will abs…

> It's always surprised me how many people do not know that water is incompressible!

Interestingly enough, they're right (though they may not know it) since the article is about its ability to compress under the right circumstances!

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