Dehydrated water free sample

vyseyboy

Stephen_Leak wrote: »

Compressed water would be useful, though.

Wouldn't want to be around when the container inevitably exploded, though!

I think they actually send out packages of air or a powder or something.
Clever people... making money.

jonathanbriggs

Stephen_Leak wrote: »

Compressed water would be useful, though.

I think you can already buy compressed water - some fire extinguishers for example - but they're v v heavy....

withabix

jonathanbriggs wrote: »

I think you can already buy compressed water - some fire extinguishers for example - but they're v v heavy....

Water fire extinguishers are pressurised with Carbon dioxide. The water is hardly under any pressure at all - only enough to get it out of the extinguisher. A 20 litre fire extinguisher contains 20 litres of water. It doesn't magically turn to 30 litres of water when you press the trigger!

Water is very hard to compress and requires very high pressures to do this.

If you compress water, ulitmately it will turn to ice.

If you expand water, ultimately it will turn to gas.

miss_phish

withabix wrote: »

Water fire extinguishers are pressurised with Carbon dioxide. The water is hardly under any pressure at all - only enough to get it out of the extinguisher. A 20 litre fire extinguisher contains 20 litres of water. It doesn't magically turn to 30 litres of water when you press the trigger!

Water is very hard to compress and requires very high pressures to do this.

If you compress water, ulitmately it will turn to ice.

If you expand water, ultimately it will turn to gas.

Amazing the things you learn on this site...:T :rotfl:

shandypants5

withabix wrote: »

Water is very hard to compress and requires very high pressures to do this.

If you compress water, ulitmately it will turn to ice.

If you expand water, ultimately it will turn to gas.

I thought water (or any liquid) was impossible to compress..

And although your right about the expanding into a gas, compressing water wil not make ice..
Ice is actually less dense than water thats why it floats.

vyseyboy

shandypants5 wrote: »

I thought water (or any liquid) was impossible to compress..

And although your right about the expanding into a gas, compressing water wil not make ice..
Ice is actually less dense than water thats why it floats.

Not impossible, just much harder than for gasses, so much so that it's rarely done for any practical everyday purpose.

And spot on about the ice: In fact compressing ice makes water,... so iceskaters can glide on a thin cushion of water due to the pressure from their weight.

Pity no one employs people for trivial knowledge like this...

withabix

Look at a phase diagram for water.

Increase in temperature OR decrease in pressure -> ulitmately 100% gas
Decrease in temperature OR increase in pressure -> ultimately 100% solid

Water takes up more space as it freezes because the molecules move further apart and any dissolved gases come out of solution (hence the bubbles in an ice cube)

withabix

vyseyboy wrote: »

In fact compressing ice makes water,... so iceskaters can glide on a thin cushion of water due to the pressure from their weight.

That's more to do with release of potential energy in the form of heat energy.

shandypants5

withabix wrote: »

Look at a phase diagram for water.

Increase in temperature OR decrease in pressure -> ulitmately 100% gas
Decrease in temperature OR increase in pressure -> ultimately 100% solid

Water takes up more space as it freezes because the molecules move further apart and any dissolved gases come out of solution (hence the bubbles in an ice cube)

OK..so if the molecules end up turther apart..then how will compressing them achive this?

Allso ..why isnt the bottom of the sea frozen if pressure causes ice?

vyseyboy

Pressure doesn't cause ice... it makes the stuff tend towards the liquid phase. That's what the last few posts were trying to say, methinks.

And the sea is super salty, and mobile too, which I guess would help.... and if any bits were frozen, they'd float to the top, being less dense than water.