Unique properties of water

Water is plentiful and much needed to sustain life. Water is made up of two simple elements, Hydrogen and Oxygen. Two gases that combine to create a liquid that we call water.

Elements expand when heated but not water. It expand when cooled instead. This brings a question I have in mind.

let’s say we hollow out a cannon ball where we have an inch thick shell. Fill it full of water and seal it good like a screwed in plug.

Freeze the ball.

Now will the water bust the ball open?

Water expands when heated (expansion of the ocean water due to global warming is a large part of the reason for rising sea levels). Except for a narrow range where it expands when cooled from 4 C to 0 C, and when it freezes. Whether freezing water would burst your sphere depends on the strength of the sphere. Surely you’ve had the experience where an accidentally frozen bottle of liquid cracked open? Glass isn’t very strong in tension but iron or steel is stronger.

Water expands and contracts with changing temperatures just like any other material. You can make a water thermometer. However, it also expands a lot as it freezes, about 9%. I think this has been discussed numerous times before. As I recall, it can produce over 30,000 psi as it expands. So your cannonball would have to be able to withstand that much pressure. And be truly filled with water, no air pockets.

If it was solid enough to resist that much pressure, the water converts to one of its other forms of ice that does not expand any further.

Dennis

Beware of creating ice IX! :slight_smile:

My youngest was gifted and very curious. When he was about 6, I observed him making a hollow sphere from clay; it had a hole which he used to fill the interior with water. When it was completely full, he carefully sealed the hole, and then placed the sealed sphere in the freezer. Several hours he returned, took the sphere out, looked at it (it was cracked with ice extrusion from the cracks) and muttered to himself…“So water really does get bigger when it turns to ice.”

As a note, water does shrink when it gets colder. It is only with the phase change to ice that the volume increases. That is why cold water sinks, and ice floats. Handy, because otherwise lakes would freeze solid, and life probably wouldn’t exist on earth.

Not quite true. As I noted above, water’s maximum density is at 4 C. Cooling from a higher temperature to 4 C causes water to contract, but continue cooling between 4 C and 0 C causes expansion. Freezing causes even more expansion.

Note that expanding when freezing is not a unique property of water. Bismuth, silicon, gallium, antimony and germanium are elements that do the same. And there are of course many compounds that do likewise.

Yeah, there aren’t very many other substances with that property, but there are a few.

Funny, I was so sure that water don’t expand when heated but the ocean part explained it did. Looks like I need to go back to my science classes again.

There are really other elements that expand when cooled? I thought water only do that.

An amazingly high heat capacity and being the “universal solvent” due to it’s polarity are two properties that I haven’t seen mentioned above.

The heat capacity of water higher than any other common substance.

This is what I was going to say (heat capacity). It really is amazing.

Water’s heat capacity isn’t all that remarkable. All substances have close to the same heat capacity, if you look at them on a per-molecule basis (or per-mole, if you’re allergic to scientific notation) instead of per-mass. Water just stands out because it has a low molecular mass (i.e., a lot of molecules per mass), and most other things with molecular masses that low are gases.

As for being a universal solvent, it dissolves both kinds of substances, [del]country and western[/del] polar and ionic. Which is already pretty far from “universal”, and even as far as that goes, there are other polar substances, like alcohol, which dissolve pretty much anything that water does and then some.

I remember about the high heat capacity of water. The microwave oven was a good example. Normally it take 3 minutes to bring it to boiling temp. Run it for 5 minute and you have a dangerously super heated water!

How much would the contraction of the iron cannonball add to the pressure caused by the expansion of water?

Is there a nice simple explanation for WHY water has a higher density in its liquid phase?

The molecules can pack up more. I know, it’s kind of “no shit Sherlock”. But get a bunch of V-shaped items and bunch them up willy-nilly; see how much space they occupy. Now take the same items and arrange them in neat cubic positions: it takes up more space.

I see that my question was much too simplistic and naive. Ice-VII is much denser than liquid water and occurs naturally on Earth among inclusions found in natural diamonds !

It’s more of a hexagon-based shape. (Think snowflakes.)

The "V"s can fit together a little tighter when part of one “V” can fit into the notch of another “V”. When freezing happens they want to form a ring-shape due to polarity and the "V"s make it a hexagon. See here. (That person sure loves ice. Lots of interesting info.)

Depends how cold you get it. If pressure keeps the water from expanding, the water won’t freeze. I put a bottle of beer in the freezer once, and took it out thirty minutes later. It was still liquid, but when I opened it (relieving the slight pressure that the bottle was able to bear), the beer turned to slush and started slowly erupting out of the bottle.

The flip side of the above assertion is that if you confine water and cool it to a very low temperature, you can generate very large pressures. Many years ago I saw still photos from the exact demonstration you described, i.e. a hollow iron sphere was filled with water and sealed. But they didn’t just put it in the freezer, they put it in a bowl full of dry ice (-109F). At that temperature, the water developed enough pressure to shatter the iron sphere in an explosive fashion and immediately freeze once the pressure was relieved.

I am sure that the heat capacity of baked potatoes must be higher. This thing has been on my plate for 5 solid minutes and still burnt the #$%& out of my tongue!:frowning: