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ice cube floats other solids don't

why do ice cubes float when solids are suppose to sink?
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hoN3yaNg3LpNai
Asked:
hoN3yaNg3LpNai
2 Solutions
 
hoN3yaNg3LpNaiAuthor Commented:
caN u aNswer this pLs... beacausE it's My hoMewoRk aNd it's duE toMorrow... tNx...
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GwynforWebCommented:
hoN3yaNg3LpNai  
  Ice  floats because it is less dense than water, most types of wood and insulation foam for instanse float as well for the same reason.

When an object is emmersed in water the force on it is equal to the weight of water it displaces so if the object is less dense than water the weight of water is more than the weight of the object so it floats. The other way around and it sinks.

Hope thet helps

GwynforWeb
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andyalderSaggar makers bottom knockerCommented:
Hydrogen bonds -www.pa.msu.edu/sci_theatre/ask_st/101294.html

Here is a slideshow (with half the words missing probably because the lecturer does not know how to spell)
www.mast.udel.edu/200/lecture%204/Lecture4%202002/sld005.htm You'll see how open the lattice of frozen water is compared to liquid water.
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grg99Commented:
Ice floats because water has this strange property:  as you cool water, it gets denser (heavier per unit volume), so it tends to sink, but then at 4 degrees above freezing, it starts to EXPAND!  So a given volume of ice weighs slightly less than the same volume of water.



 
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SunBowCommented:
Interesting, all that. And to think that over half surface of globe is.... water, with its inherent properties.

Ask your parents about your homework. In this case, as I recall, a typical parent may say that they always use warm water, not cold, for making of ice cubes.  Maybe someone other than me can explain that, I'd think you'd want to start with cold water. My parents weren't scientists with that kind of answer, they just knew what worked, not why.
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aburrCommented:
There are very few sustances which expand upon freezing. Water is one of these (another is gadolinium). This circumstance is very fortunate for life on earth. If it were not so most of our lakes would be frozen. Most of our fish would freeze in winter. Rocks would not be broken down to soil. All sorts of bad things would happen.

By the way the same amount of warm water will not freeze faster than the same amount of cold water. (In some of the experiments, some of the warm water evaporates so that there is less water to freeze)
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DocDosterCommented:
Yes. Warm water will evaporate leaving less water to freeze, plus you get the added bonus of evaporative cooling.

Doc
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halfcent50Commented:
Wood floats - and it felt pretty solid the last time I got hit in the head with a 2 by 4
 |:-(
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hoN3yaNg3LpNaiAuthor Commented:
tNx y'all
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hoN3yaNg3LpNaiAuthor Commented:
tNx y'all
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GwynforWebCommented:
hoN3yaNg3LpNai, You should now must choose i.e. accept the answer you found most useful, by clicking next to it. That is the way this site works.  
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leojlCommented:

hi,

you have gotten a lot of good comments here.

now it is your turn to tell us what your screen
name hoN3yaNg3LpNai  means.

also as gwen said to select an answer

leo
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Thibault St john Cholmondeley-ffeatherstonehaugh the 2ndCommented:
SunBow,
I have heard that it is boiled water, not just warm water that freezes quicker. I think the idea is that boiling the water causes it to release some dissolved gasses that would otherwise slow down the freezing process.
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andyalderSaggar makers bottom knockerCommented:
Ice cubes don't float in boiling fat in the chip pan, they explode setting fire to the kitchen.
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BretKCommented:
From what I understand, water expands when it frezzes because ice is a crystaline formation, with the molecules in an orderly pattern, where liquid water does not have this orderly pattern. Becase the frozen water molecules are in a pattern, there is more empty space between the molecules, which cause the ice to expand and makes it less dense than the liquid water, therefore it floats.
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andyalderSaggar makers bottom knockerCommented:
Solid iron has a crystaline structure but it sinks in molten iron. Without the hydrogen bonds it would form a tighter lattice and sink.
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BretKCommented:
I did not mean to say that all crystaline solids would float in their non-solid counterparts, but I only meant to say that this was the case for water. Perhaps I was a bit unclear on that point.
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VGRCommented:
BretK is right for ice vs water.
a lot of solids do float over water (depending on its density, Dead Sea water is not like Annecy's Lake one ;-)
Also, some woods are denser than 1 and do sink ;-))
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TheBeaverCommented:
If hoN3yaNg3LpNai is so freaked out by ice floating then for the next week only eat carbohydrates and then do a big turd. I bet you it floats!!!
Now, try and flush that sucker. The floating poo not only floats but also disobays the physics of the flush toilet.

[Cue: Twilight Zone theme]

LOL
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tncbbthositgCommented:
Solids are not "supposed" to sink.  It depends on the density.  Water happens to be one of the very very very few compounds in which the density decreases when heated and frozen.  It is also one of the only compounds that expands when heated and frozen.  It's very interesting.  It is this expansion that increases the boyancy (i.e., the displacement is greater than the mass) so it floats.  Foam is also a solid and it doesnt sink.  That is because the mass is so little and the volume is so high.
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CraggCommented:
The correct answer is from grg99 explaining about water expanding at +4. I remember this from high school.

I just thought that I would add this interesting fact, that if not for this property, there probably would be no life on earth. As ice would be formed, it would sink, allowing the upper layer to freeze and sink. With this cycle repeated over time, the rivers, lakes, and oceans would eventually freeze solid.

Cragg
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KodeBunnyCommented:
About using warm water for making ice: use warm water to make ice because the ice is clearer without alot of air bubbles.
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JimCoffeyCommented:
Warm water melts the thin layer of frost and allows direct contact between the ice cube tray and the cooling coils. Frost is not an effecient heat transfer medium and by melting the frost first you get better heat transfer and thus faster freezing. This is mainly true for old refrigerators (not the new frost free ones) which is why your parents remember this trick and you don't.  We actually did the math when I was taking heat transfer as a chemical engineering student (many, many years ago).

Jim Coffey B.S. Chemical Engineering Texas Tech University 1984.
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GwynforWebCommented:
Jim,
  Interesting piece of work. The higher temparature at the interface of the water with the cooling  medium also increases the rate of heat transfer. Starting with warm water by the time the average temparature of the water is the same as that starting with cold water, the temparature profile across the water to be frozen is flatter, (ie the the inner regions are colder)  
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GwynforWebCommented:
KodeBunny,
   The best way to make clear ice is to cool it from the bottom, the air rises to the top. Insulate all but the bottom of the container and put it in the freezer.  
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SunBowCommented:
Done yet, hoN3yaNg3LpNai?
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SunBowCommented:
KodeBunny> use warm water to make ice because the ice is clearer without alot of air bubbles.

Interesting, I was about to ask that one. OK, I have similar one for oldtimer, maybe Jim?  First, there is a major differences between clear ice and cloudy ice. So I am guessing this is more about the air that can be trapped inside freezing water.  Like any could crystal, ice can be 'crystalline clear' such as to be like window glass.

Q1) since cloudiness for crystals indicates presence of impurities, is that same for water? Namely, that fewer air bubbles make it more clear?

JimCoffey> This is mainly true for old refrigerators (not the new frost free ones)

Now, what about older ones: Ice Boxes?  Remember? Before 'everyone' could afford electricity and electical appliances such as air conditioning.  You get to go to supplier to pick up some 'cubes', and steer the horse to pull the wagon of goods to apartment complex, then heft a block of ICE upon your shoulder and carry it up a few flights of stairs (no elevators either). So people'd pay well for that, and use it to cool their perishables.

Q2) Wasn't this ice, in blocks, very very clear, compared to more typical mass-produced teeny cubes?

Q3) Given the density issue, of some ice having less entrapped air molecules being more dense - could it be

Q3a) very dense ice cube does not float after all? Haven't we had a drink that had a cube that would not float all the way to the top?

Q3b) Could it be that ability of ice to float may be more due to entrapped air molecules (which are lighter than liquid water)?

tncbbthositg> Solids are not "supposed" to sink.  

hmm, dead fish float, and they are solid. To stay underwater they must be alive and swimming? Hmm, dead people sink in water, to remain on surface they must be alive and swimming? Aren't people solids?  I recall some exceptions, where some people claim to float when immobile, and some fish seem to remain underwater when motionless. Exceptions. Exceptions?

hmm. Go for walk on frozen lake. Seems the more cloudy the appearance, the more solid support one had for walking, while the more clear in appearance, the more likely it won't bear the weight, and will not remain atop surface of lake for long.
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SunBowCommented:
GwynforWeb> Insulate all but the bottom of the container and put it in the freezer

I meant to also ask how ice blocks are made. Is that part of the answer?
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CraggCommented:
I believe that the question should have been asked to say "a compound whos OWN solid floats on its liquid", whuch makes grg99's answer the correct one.

Now how did this digress to cloudy and clear ice?

Since his homework was due the following day, he has probably long forgotten his question.
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SunBowCommented:
Don't solid leaves float?

OK, I can google too, so I did, and...

hoN3yaNg3LpNai> why do ice cubes float when solids are suppose to sink?  

Answer: This was design to benefit ice harvesters. Ex:

http://members.rogers.com/canadianbranchline/retailice.htm

Interestingly, the industry was first killed off when people had no money in TheDepression, and had the eyesores burned down. Then later, after industry had resurfaced, a day cam when people found themselves affluent and had the eyesores burned down.

GwynforWeb> The best way to make clear ice is to cool it from the bottom, the air rises to the top. Insulate

according to that link, common insulator was sawdust! hmm, isn't sawdust another solid - that floats? Sure sounds like it'd be cheaper than the insulating materiel THEY sell us.

A short workweek was only 16 hour days, six days a week.

> created their own artificial ice, but customers were not happy with the yellow residue it left

?! interesting. I'm sure there's a question there, but it eludes me. Seems like a good sprinkling of sawdust was more pure - and, it could be easily removed when desired.

Thimble Ice vs Tube Ice:
http://www.sparkling-ice.com/packaged_ice.htm

Dry Ice:
http://www.wittemann.com/ice.htm
http://www.tomcoequipment.com/abouttomco.htm

(isn't Dry Ice a solid that floats? but it's liquid form ....)

Flake Ice:
http://www.haisan.com/Corporate_info/Vision_mission.asp

Ice Making Commerce:
http://www.commerce.gov.sb/Divisions/Industry/project_profiles.htm

Ice Block Maker:
http://www.minus40.co.za/IceBlockMaker.htm

Ice Block Sculpture:
Turquise Ice:
Real Ice:
Ice Bar:
Ice Luge:
Fixed Ice (using water):
http://www.snow-business.com/snowdisplay/icesculpture.htm
Vodka Ice:
http://www.icesculpture.co.uk/html/page5.htm

Crushed Ice, Ribbon Ice, Flake Ice vs Tube Ice, Block Ice vs Small Ice, Natural Ice vs Artificial Ice, Sea Water Ice vs Ordinary Ice:
http://www.fao.org/wairdocs/tan/x5901e/x5901e01.htm

>Block ice manufacture

>The traditional method is to immerse cans filled with water in a bath of low temperature brine. Size of block may range from 55 lb to 300 lb or more; 3 cwt is considered to be the largest size of block a man can conveniently handle. A thickness of at least 7 inches is desirable if the block is to remain stable when being moved about on edge.

> sea water ice has no fixed equilibrium temperature

- ice is its own thermostat... or it may no longer its own thermostat...

...

<phew> er, is this thread closed yet?
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SunBowCommented:
Cragg>  Now how did this digress to cloudy and clear ice?

Observation: Some Threads do digress when unattended. Many just wilt away.

Cragg>  due the following day, he has probably long forgotten his question.  

Agreement, except person's interest ran at least three days, as follows:


From: hoN3yaNg3LpNai
Date: 02/20/2003 09:25PM PST
Status: Waiting for Answer

Comment from hoN3yaNg3LpNai  02/22/2003 01:54PM PST  
tNx y'all

Comment from GwynforWeb  02/22/2003 06:01PM PST  
hoN3yaNg3LpNai, You should now must choose i.e. accept the answer you found most useful, by clicking next to it. That is the way this site works.
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leojlCommented:

I bought a Richard Jolley 1996 Martini glass
today at a thrift shop for US $1.00 + tax (8.5%).

I washed it real good and tonite I made a martini.
I put 4 big sturdy ice cubes in the glass ... then I
added 2 olives ( and some liquid from the olive bottle).
Then I poured in some gin ...perhaps 2/3 level in the
glass which already had olives and ice cubes. Then I added
a very modest dash of Martini and Rossi vermouth.

This was a scientific experiment to study the flotation
character of the solid ice cubes. I am now on my 4th
experiment. Both the ice cubes and the olive are in a
flotation mode .

... oops ,  I just touched the olive and it went to the bottom ... the ice cubes are still on the top ..

clearly further study is warrented here .. I will close
for now and hand off this study to other EE people.

leo
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JimCoffeyCommented:
Grg99's answer is correct, as is mine.  Frozen H2O will always float, the ice cubes at the bottom of your glass are being held down by the other ice cubes at the top.  Each individual ice cube will float if placed by itself in a cup of water.

This thread is digressing - the original author needs to decide who gets the points.

Cloudy ice can be caused by several sources - most have been identified above.  To clarify the issue ... cloudiness can be caused by:

entrained air bubbles
various solid contaminants such as lime, scale, stuff from your pipes, etc.

Enjoy - Jim Coffey  B.S. Chem Eng - old timer (yuck).

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GwynforWebCommented:
 I think hoN3yaNg3LpNai interest in this question ran out ages ago, although he is probably getting maliled bombed with notifications.

  Commercial ice block makers for clear ice for carving (yes they do exist) remove all the crud and air by starting with warm water and freezing from the bottom, the contaminants and air form a layer on the top of the clear block that is then removed. Most solid dissolved contimants will be expelled if given space by the freezing ice. Icebergs although coming from sea water are essentially frozen distilled water.
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patrickabCommented:
leojl - now that sounds like a sensible experiment that could be repeated for verification as often as needed.

By the way the original question is faulty. Who said solids are 'supposed' to sink? I can't remember anyone saying such a thing. It's just an incorrect assumption.

After all almost everything will float on mercury which I keep on being told is a super cooled solid - but who cares when few of us have ever seen it solid?

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leojlCommented:

patrick  ... thank you for your support of
the experiments upon which I have embarqued.

the eternal quest continues.

I agree that the original question was flawed
, but it did bring forth some very learned comments
that were well worth reading and even studying.

leo
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GwynforWebCommented:
I dropped peanut in my usual midmorning glass of champagne and it sank, and now it is floating, and now it has sunk again, and now it is floating again ....
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leojlCommented:


gwyn  ...  salted peanuts do that in beer also.

quite amazing ...  perhaps worthy of an EE question.

leo
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GwynforWebCommented:
leo, If truth be told I have not ever actually done it with champagne and do it with beer as well. It is really rather funny when you are drunk. The question as to why the peanut has to salted is an interesting one. Gwyn
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SunBowCommented:
How about unsalted ones in a Marguerita? Hmm, I agree this may well warrant its own thread, in whatever TA is current.
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SunBowCommented:
OK, I did one if'n you're game:
Title: A scientific look at liquids and solids.
http://www.experts-exchange.com/Miscellaneous/Math_Science/Q_20556569.html
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leojlCommented:

gwen ... darn .. I had pictured you with
your usual 10 am glass of champagne and
a bowl of peanuts  ... and wearing
a white lab coat to pursue your study.

sunbow, I commend you for
" A scientific look at liquids and solids."
**********************
I will make a contribution, but not tonite.
It is 10:34 pm here on the west coast USA.
I am watching TV reports on a war of which
I do not approve.

In 1947 I went to Japan as a Pfc in the
1st Cav Division for the US occupation force.
In the year 2003 we are still there. Not the
1st Cav ... I think they went to Korea, but
US troops are still in Japan, Okinawa, Germany
etc, etc, etc...

Certainly the USA can occupy Iraq. I expect
that some of my grandchildren and my great
grandchildren will be in the occupation force
there.

I just hope this war ends quickly with minimum
loss of life on both sides.

leo


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SunBowCommented:
> US troops are still in Japan, Okinawa, Germany

I made it to Okinawa, where history has enemy seeking shelter in cave, told to come out 'or else', and cave entrance sealed shortly thereafter. Handling hills of Afghanistan recall that back to mind, and now not too dissimilar, the underground bunkers in Iraq.

> I am watching TV reports on a war of which I do not approve.

I quit TV awhile back.

> sunbow, I commend you for

Thanx, I think with little immediate influence on overseas affairs, another diversion here more in order. There's already two participating in healthy discussion, join in any time. My hope is it gets as good a blend as this one.

> my great grandchildren will be in the occupation force
there.

I'm doubtful on that, but surely they'll still be paying for it.
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jamesxiCommented:
hoN3yaNg3LpNai, are you talking about Ice I, or Ice III?
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patrickabCommented:
I particularly liked this explanation to the original question:

Dr. Arnold G. Gill

Astrophysician, Malaspina University-College, British Columbia, Canada

The expansion has to do with the peculiar molecular structure of water. Within the limits imposed by this keyboard, a water molecule looks like

                        O
                       / \
                      H   H

Each of the hydrogen atoms weakly attracts nearby oxygen atoms, so water binds together. When liquid, the binding is weak, but when solid, the bonds become quite strong, and constrain how the molecules may arrange themselves as a crystal. In its liquid state, the molecules are free to roam around wherever they wish. However, in its frozen state, the water molecules form a hexagon (six-sided figure), giving the beautiful six-sided snowflakes that we are all familiar with. In this state, the molecules line up approximately like the sketch below

                     H2O
                   /     \
                 H2O     H2O
                  |       |
                 H2O     H2O
                   \     /
                     H2O

with the lines showing the molecular bonds holding the molecules in place. Notice that the center is empty! In its liquid form, with the molecules moving about freely, you will find an H2O molecule in the center of such a structure, but not in its solid state. So, a given amount of water will use up more room as ice than as a liquid, because of the empty space that appears as it freezes. Thus, ice is less dense and it floats. (And in case you are wondering, the center is EMPTY; it is NOT filled with air. Air bubbles are extra effects that help to float ice, but air bubbles are not needed to get ice to float.)

You've probably heard that 90% of an iceberg is under water. This suggests that the density of ice is about 10% (1/10) less than that of water. Yet, from the simple diagram above, there are 6 water molecules where before there were 7 - a difference of about 14% (1/7). Why the discrepancy? While frozen water has a unique crystal structure, it also acts like every other substance in the world - it contracts when it cools. That is, the average distance between adjacent water molecules still decreases when water freezes (in the diagram, the lines connecting the molecules get shorter). The net result is that the group of molecules shrinks, but the center remains empty - or 1/7 shrinks to about 1/10.

As far as I know, water is unique. However, there may be more exotic liquids that exhibit similar properties. I doubt that you would find any of them outside of a lab.
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leojlCommented:
hello

Icebergs are frozen fresh (non-salt) water.
Salt water is more dense than fresh water.

My wife tried to sit on a rock in the Dead Sea,
but she kept popping up to the surface ... she is
dense ( she is NOT contributing to this ) but at
the salty Dead Sea she could not sit on that rock.

So the fresh water ice vs the salty sea might help
explain the 1/7 vs 1/10 problem.

leo
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GwynforWebCommented:
Leo
  "Icebergs are frozen fresh (non-salt) water" this is not entirtely true, some are frozen sea water and are just as pure. Hudson's Bay for instance freezes every year and produces ice blocks easily big enough to be categorised as icebergs at break up in June/July.

GwynforWeb
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leojlCommented:

this url is one of many iceberg hits on google.com

leo

http://www.qikiqtarjuaq.com/glaciers-ice-caps-and-icebergs.htm
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GwynforWebCommented:
Leo, I believe mariners use a definition based on ice block size. Perhaps I shoild have been more careful in my terminlogy, but my initial observsation still stands.

Gwyn
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TheKaseKaiserCommented:
Simple. Ice is less dense than other solids. Wood is also one of these things! Please hurry up with teh points!
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GwynforWebCommented:
TheKaseKaiser, Thanks for clearing eveything up now I understand. hoN3yaNg3LpNai give TheKaseKaiser the points. :-)
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b_vishwajitCommented:
:)
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SunBowCommented:
RobinD> SunBow, I have heard that it is boiled water, not just warm water that freezes quicker. I think the idea is that boiling the water causes it to release some dissolved gasses that would otherwise slow down the freezing process.  

Similarly, for making coffee use cold water, as it still has the extra dissolved gases that already hot water does not.
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andyalderSaggar makers bottom knockerCommented:
Frozen sea ice doesn't really count as icebergs, it breaks up much easier than proper frozen rivers.
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SunBowCommented:
- or proper frozen mountains or poles
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andyalderSaggar makers bottom knockerCommented:
Just how many poles are there? Answers in http://www.experts-exchange.com/Miscellaneous/Math_Science/Q_20591452.html please.
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VirtualThugCommented:
the reson why an ice cube floats is because its half soild and half liquid  thats why it flots and other soilds dont (because its not a full soild)
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jamesxiCommented:
VirtualThug, no, the real reason their is only one solid on the planet that will float (ice), is because the substance is surrounded by liquid around the immediate edges, causing it to slip to the top of the water. If you have ever tried to tightly grasp ice you will notice it sometimes flies up. And even if that were not true, it would still float because it has so many air bubbles, which are caused by oxygen-rich water freezing and forcing the oxygen into bubbles via amino-peptide reaction. And of course the ionic exchange between the water and ice. I think the main idea here is that this website is called "experts exchange". I have to doubt if you know the difference between Ice III and Ice IV.
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andyalderSaggar makers bottom knockerCommented:
I prefer Ice 1c, because it is cubic and ice is meant to come in cubes so they fit properly into the martini ;-)

Great interactive at http://www.sbu.ac.uk/water/ice1c.html
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gemartiCommented:
jamesxi: Ice isn't formed from an amino peptide reaction. Where did you get that from?

Ice in the presence of water is in a melting state.



Process                 Changes           Heat gained or lost by the air
                  From             To
Condensation      vapor          liquid        2500 J/g or 600 cal/g
Deposition        vapor          ice           2833 J/g or 680 cal/g
Evaporation       liquid         vapor        -2500 J/g or -600 cal/g
Freezing          liquid         ice           333 J/g or 80 cal/g
Melting           ice            liquid       -333 J/g or -80 cal/g
Sublimation       ice            vapor        -2833 J/g or -680 cal/g


As water freezes into ice, the molecules become frozen in place and begin to arrange themselves in a rigid lattice structure.
The structure that forms in the solid ice crystal actually has large holes in it.  Therefore, in a given volume of ice, there are fewer water molecules than in the same volume of liquid water.  In other words, ice is less dense than liquid water and will float on the surface of the liquid. 




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gemartiCommented:

In simple terms....Ice floats because it is lighter than water.

Ice in water is in a state of flux between ice and water. As the Ice's core temperature rises, it will melt the outer edges. The warmer water will absorb the cooler temperatures until eventually the ice is totally absorbed into the water and is no longer floating.
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jamesxiCommented:
gemarti, as a quantum phycasist, i may be a little bit above your level. However, I can say that at the quantum level ice has no latticework, but rather an extenuatory range of bottom/charm reactions. And no, I am not talking about the Lucky Charms cereal as most people such as yourself would think.

To extrapolate on what i am saying here, is that this post was obviously started by a troll: "caN u aNswer this pLs... beacausE it's My hoMewoRk aNd it's duE toMorrow... tNx..." Obviously nobody would post that seriously. So I am not answering it seriously, and I would hope that anybody can see that!
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