Melt Ice Quickly: Best Ways to Do It

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In summary, the best way to melt ice in a short amount of time without using any chemicals is to maximize the surface area in contact with air and consider factors such as low pressure and high temperature. Breaking the ice into small pieces, increasing pressure, and using a vertical tube to create a cold draft are all suggestions for achieving this. However, it is important to note that any external sources for heating, such as boiling water, are not allowed. The ice must be broken up during the experiment, not beforehand.
  • #1
HK911
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Question: What is the best way to melt ice?
 
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  • #2
I am working on this project where we have to melt some ice in about 2 mins. The experiment will be taken place indoors, at room temperature. We have to melt as much ice as possible in that time. No salt or any chemicals can be used. Conduction or convection is all we can do. Any suggestions for materials or a way to design this.
 
  • #3
If you can't use chemical means then it is simply a matter of getting as much heat into the ice as quickly as possible.
A couple of factors to consider
Ice is a poor conductor of heat so just heating the outside of a large block isn't a good plan.
Water has a very high heat capcity so heating the melted water will waste a lot of energy.
 
  • #4
If it's allowed, break the ice into as many small pieces as you can to maximize the surface area in contact with the air.
 
  • #5
Melting temperature also depends on the pressure: increase of pressure will decrease melting point. If ice is at T=0, then any increase of pressure will cause some ice to melt instantly (until melting uses so much heat that T reaches new melting temperature). The higher the pressure, the larger part of the ice will melt.
 
  • #6
Obviously low pressure and high temperature, however you achieve that.

Can you think of ways to lower pressure and simultaneously increase temperature? If you can then any method will be only using convection and conduction.

Of course as Danger said if you could atomise or at least break it down very quickly before you start, that would be good but I doubt you can do that easily. Get a lump hammer and crush it all to hell then stick in a bell jar, which gradually but obviously very slowly sucks the air out and heat said bell jar.
 
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  • #7
No, pressure should be increased to melt ice. But I calculated this effect is to weak to achive impressing results: about 5*10^-5 of the mass of ice will melt for each bar of pressure increase.
This metod would make sense only if we were limited to very short times.
 
  • #8
Lojzek said:
No, pressure should be increased to melt ice. But I calculated this effect is to weak to achive impressing results: about 5*10^-5 of the mass of ice will melt for each bar of pressure increase.
This metod would make sense only if we were limited to very short times.

Ok why would increasing pressure work better than decreasing pressure and heating? Not sure I get that?
 
  • #9
I cannot show that increasing pressure will work better than decreasing pressure, but I can explain why increasing pressure leads to melting :

http://www.bae.uky.edu/~snokes/BAE549thermo/gasesv1.jpg"

You can see on this diagram that when you are bellow the triple point temperature and around the 1 kPa, increasing the pressure will lead to melting. But it only works for water.

As I've said, I don't know which way is the fastest.
 
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  • #10
TeTeC said:
I cannot show that increasing pressure will work better than decreasing pressure, but I can explain why increasing pressure leads to melting :

http://www.bae.uky.edu/~snokes/BAE549thermo/gasesv1.jpg"

You can see on this diagram that when you are bellow the triple point temperature and around the 1 kPa, increasing the pressure will lead to melting. But it only works for water.

As I've said, I don't know which way is the fastest.

I think that only works for cool ice though, if you heat it and lower pressure, I'm not sure but I think it may well work better.

You do understand why ice is less dense than water at certain temperatures?

I don't know for sure which is better either given two minutes. But I guess if you can decrease pressure and heat it fast enough, it may well work out better.
 
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  • #11
Thank you very much for the comments. Changing the pressure would be best, but unfortunately, we can't use any external source. The only external sources we can use are the room temperature and gravity for instance.
 
  • #12
Take the ice, break it up onto some sort of container. Get something that's very heavy and place it on top of the ice chunks, then rotate the container while keeping the heavy item on the ice stationary.

I see something like this
{ || } <--- the thing on top of the ice
[container]

I haven't done this, but since you can't use chemicals, maybe you can use the friction and pressure that gravity exerts on the "thing on top of the ice" to melt the ice.

I'm not sure HOW much ice you're using, which is why I suggest breaking them up into bits.
 
  • #13
Definitely break it up if you can. Put it in a vertical tube open at both ends so that will generate a cold draft downward. This will draw warmer air into the top and down across the ice. It would be good if the ice were on a screen of some sort so the water could drain away and the air could flow around each piece of ice. But as the pieces get small they will fall through a screen.
 
  • #14
I'm surprised nobody simply suggested pour as much boiling water as you can into the ice. If that's not allowed, then pee on it. Or is hot water considered a chemical?

After smashing up the ice.
 
  • #15
If you're not allowed to physically crush the ice, heat it on a wire rack. Allow the ice to sink into the rack and the water to drop off.

But crushing is better.
 
  • #16
Thanks a lot of the comments once again. Heating is not allowed. You can only heat it up using the light in the room which is useless. Also the ice cannot be crushed before the experiment, it must be crushed by some means during the experiment. The vertical tube is a great idea. But in terms of the melting water, get rid of it or let the ice sit in it?
 
  • #17
it is possible to generate some frictional heat during the experiment? Is it allowed to bring some tools or materials for the test? If it is allowed, bring a meat tenderiser to crush and apply pressure to the ice.
 
  • #18
I think, drain the water away so you don't use some of your heat to evaporate the water. How 'bout building a heat sink into the ice container.
 
  • #19
Use a thawing plate. Big block of metal (copper would be good, aluminum is cheaper). Maybe cut some grooves into it for drainage if you're feeling particularly creative.
 
  • #20
How much ice is being provided?
 
  • #21
Schrodinger's Dog said:
Ok why would increasing pressure work better than decreasing pressure and heating? Not sure I get that?

Water (H2O) is unusual in that the solid phase is less dense than the liquid phase, hence ice floats on water - a rare physical property which actually is essential for life as we know it*.

This relates to the fact that under typical surface conditions (i.e. what might be considered normal pressures and temperatures at the surface of a planet) H2O has a negative Clapeyron slope - that basically means that the melting temperature goes down as the pressure is increased. Consider this: imagine you had a body of water all at the same temperature, from experience we know that the ice will form at the surface of the water (I guess we have to be careful here - maybe that happens because the air above the surface is colder, but I believe in laboratories we can control the conditions and can convince ourselves that it is not because of the colder air at the surface); now where is the pressure the greatest? Of course, the pressure is greatest at the bottom of the water because it has a load of water on top of it, but the ice doesn't form at the bottom - the ice forms at the top where the pressure is lowest. So does this not mean that water has a higher freezing point at lower pressures?

That's my understanding anyway.




*If ice was denser than water then the oceans would have completely frozen, because there wouldn't have been an insulating cap of ice at the top to stop all the water from getting very cold (and then freezing solid), life needs liquid water, ergo, if the oceans were frozen we wouldn't have life.
 
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  • #22
Probably what I'd do is crush the ice, just as much as possible. If you can somehow reflect the light & focus it as well, that might help. Maybe even the classic black cloth might work... then again, I'm not really sure what the rules are. It seems you can't use pressure but you're allowed to crush it? This I don't really understand. Using pressure will melt the ice, its just like if you step on ice in the winter time, it changes to water & you slip & fall. If you're crushing the ice, I'd leave it sit in the water, because it will melt faster (the classic water is warmer than ice, particles move around speed up melting of ice process).
 
  • #23
Are you allowed to breathe on it?
 
  • #24
HK911 said:
Thank you very much for the comments. Changing the pressure would be best, but unfortunately, we can't use any external source. The only external sources we can use are the room temperature and gravity for instance.


Re: Breaking up the ice...

If you can use gravity, perhaps a grid made of plates (I'm thinking the inside of an old-fashioned ice-cube tray) with heavy weights all around. If you use a wire rack as CP suggested, the ice might re-freeze after the wire passes. However, with plates you keep the ice separated and expose the increased surface area to direct contact with the plates. Exposed part of the plates will conduct heat down into the block of ice. In fact, if you have the block sitting on top of one grid and another grid sitting on top of the block, your results will come almost twice as fast (and you'll allow the melt-water to drain away, so you're not wasting heat warming it). For fastest results, sharpen the edges that make contact with the ice, so they'll cut through faster and get the extra surface area exposed; 2 minutes is not very long.
 
  • #25
What are the dimensions of the ice? Or do you get to choose?
 
  • #26
hmm

If you have windows and its a sunny day you could use a magnifying glass. Otherwise - wrap the cube in a black cloth and sit on it.
 
  • #27
place some high resistance electric coils near by the ice to melt it fast
 
  • #28
billiards said:
Water (H2O) is unusual in that the solid phase is less dense than the liquid phase, hence ice floats on water - a rare physical property which actually is essential for life as we know it*.

This relates to the fact that under typical surface conditions (i.e. what might be considered normal pressures and temperatures at the surface of a planet) H2O has a negative Clapeyron slope - that basically means that the melting temperature goes down as the pressure is increased. Consider this: imagine you had a body of water all at the same temperature, from experience we know that the ice will form at the surface of the water (I guess we have to be careful here - maybe that happens because the air above the surface is colder, but I believe in laboratories we can control the conditions and can convince ourselves that it is not because of the colder air at the surface); now where is the pressure the greatest? Of course, the pressure is greatest at the bottom of the water because it has a load of water on top of it, but the ice doesn't form at the bottom - the ice forms at the top where the pressure is lowest. So does this not mean that water has a higher freezing point at lower pressures?

That's my understanding anyway.

*If ice was denser than water then the oceans would have completely frozen, because there wouldn't have been an insulating cap of ice at the top to stop all the water from getting very cold (and then freezing solid), life needs liquid water, ergo, if the oceans were frozen we wouldn't have life.

Yeah I know that but it doesn't prove that reducing and heating would be better than increasing pressure at all.

Bodies of water would also freeze from the bottom up making life difficult to get started in the first place.
 
  • #29
Q: Can solvents be added to the ice?
A: No, nothing can be added to change the chemical composition of the ice or that creates an endothermic or exothermic reaction. Clarification: in any part of the device, no substance that creates an endothermic or exothermic reaction is considered to be passive as it is stored chemical energy. Solvents include but are not limited to fertilizer, cat litter, sand, bleach, sugar.
Q: Restricted
A: Any passive field may be used (i.e. gravity)
Q: Can we use additional water?
A: As long as it does not come in contact with the ice, ice/water mix. However, if you’d like, you may use the water from the melt.
Q: Can the ice be broken up?
A: Not prior to the testing time, and only by some passive means during the testing time…good luck with that!
Q: How about deformable materials such as sponges
A: Sure.
Q: Can the ice be dropped
A: No
Q: Can we use hot water
A: The device must start at room temperature, which includes any additional water.
Q: Restricted
A: No, a generator can not be used.
Q: Can we focus the light with lens
A: Yes, Lens can be used.
Q: How about dry ice?
A: No dry ice
Q: Can we add pressure to the ice?
A: Yes, passively. For example, a weight may be placed (not dropped) on the ice.
Q: Could you post your PowerPoint slides from lecture?
A: No, but I did post a summary of the analytical model that has more details then what I went over in class.
Q: Do we have to provide a catch basin for water run off?
A: There is no requirement for a catch basin.
Q: Exactly how big is this block of ice?
A: A 10 oz coffee cup, ¾ filled with water. This is approximately 200 mL of water.
 
  • #30
Above is a few of the frequently asked questions. If we used the plates, would it be best to place it in some sort of container? We were thinking of designing a box made from acrylic with holes in the bottom and top to all air to flow. Should be do that are just let it sit in the air with no casing around it?
 
  • #31
Gravity considered passive, eh? Because if you held the ice in callipers as it melted it would pitch to the floor, no one is dropping it, the higher up you put it the better, it would melt in no time then. :) as it would be spread over a massive surface area. Sadly I think that counts as dropped though. If you used a catalyst that increased ice melting without chemical reactions that might be passive?
 
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  • #32
Gravity is passive. But how high would you have to place the ice cube to actually have some sort of effect. The experiment would be carried out on a table. Here is some more information.

Project Statement:
The project team is to design, analyze, build and test a "passive" heat transfer device to enhance the defrost process as realized by the melting of ice. Passive means no energy input is to be utilized during the operation of the device. To remain in context with the above described devices, the ice may not be modified in any manner. The device must also begin at room temperature. A device must be manufactured by the project team. At the end of the semester a competition will be held during which the device will be judged on the basis of the ice melting rate produced, the mass of the device, and its cost. The device must fit inside a box of dimension 14" x 14" x 12"
 
  • #33
HK911 said:
Above is a few of the frequently asked questions. If we used the plates, would it be best to place it in some sort of container? We were thinking of designing a box made from acrylic with holes in the bottom and top to all air to flow. Should be do that are just let it sit in the air with no casing around it?

Open to the air would work best, I should think. I did not realize it was such a small block of ice. The inside of a metal ice cube tray would not work very well on this particular body of ice, you would only and a cutting it into two or three pieces. You will want your plates to be much closer together than this. Also, you should try to get them to line up with each other (if you use the "sandwich method" of placing one grate beneath the block and one above it).
 
  • #34
Adding pressure will indeed melt more ice for reasons explained by "billiards". A quick test is that you can press your thumb into a block of ice and create a small dimple in the ice surface.

Anyhow, I would consider making a device where ice is placed inside a spring loaded "vice". At the start, the spring would be compressed most and will exert the maximum force on the ice.

As the ice melts, the spring would cause the vice jaws to move closer but still maintain contact with the ice.

Also, I would allow the water produced to run off. Keeping the ice in water-bath will set up an equilibrium between the ice-water system and some of the water molecules may become ice again. Also, one would expend part of the energy to evaporate water.

You may also think about rigidly attaching some sort of fins for accelerating the heat transfer. Make sure that the fins are integral (read: welded) to the vice jaws. Or else, the fins would be useless if there is an air gap between them and the jaws.

I am sure you can come up with multiple designs. This is just one possible solution. However, if you want to put some mathematics to all of this, it is beyond me. Look into FEA if you want to decide between a couple of designs.

Good luck!

Another option is to concentrate the force on a small area to create more surfaces really rapidly.
 
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  • #35
Schrodinger's Dog said:
Yeah I know that but it doesn't prove that reducing and heating would be better than increasing pressure at all.
Uh, ok, you're right, but I don't remember claiming to prove anything, or even hinting that "reducing and heating would (not) be better than increasing pressure" ... whatever :rolleyes:.

Bodies of water would also freeze from the bottom up making life difficult to get started in the first place.
No they wouldn't, even if the ice formed in the deep it would float up to the surface by buoyancy. You can't be still be claiming that the melting temp of ice is higher at higher pressures, I would agree if we were talking about ice III, V, or VII, but we're talking about everyday "normal" ice here: ice I, which if you look at the http://www.homepages.ucl.ac.uk/~ucfbanf/water_ice.htm" [Broken] for water ice you will see has a negative Clapeyron slope. As I mentioned earlier this is important for life, because it means that under great ice bodies, where the pressure is high, the ice can melt more easily providing underwater reservoirs which may harbour life (chemoautotrophic life, probably) - c.f. Europa. It's also an important mechanism for the movement of glaciers, the water at the bottom of a glacier pushes the ice upwards reducing friction with the ground accomodating "basal sliding".
 
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<h2>1. How can I melt ice quickly without using salt?</h2><p>One of the best ways to melt ice quickly without using salt is by using hot water. Simply pour hot water over the ice and it will melt almost instantly. However, be careful not to use boiling water as it can cause damage to the surface underneath the ice.</p><h2>2. Can I use household items to melt ice quickly?</h2><p>Yes, there are several household items that can be used to melt ice quickly. These include rubbing alcohol, vinegar, and sugar. Simply mix these items with warm water and pour over the ice to melt it.</p><h2>3. What is the most effective way to melt ice quickly on a large surface area?</h2><p>The most effective way to melt ice quickly on a large surface area is by using a de-icing solution. These solutions are specifically designed to melt ice quickly and can cover a large area with just one application.</p><h2>4. How long does it take for ice to melt using different methods?</h2><p>The time it takes for ice to melt using different methods can vary depending on the size and thickness of the ice, as well as the temperature and method used. Generally, hot water can melt ice in a matter of seconds, while household items and de-icing solutions may take a few minutes.</p><h2>5. Is it safe to use chemicals to melt ice quickly?</h2><p>While chemicals such as salt and de-icing solutions can effectively melt ice quickly, they can also be harmful to the environment and surrounding plants and animals. It is important to use these chemicals sparingly and follow proper disposal guidelines to minimize their impact.</p>

1. How can I melt ice quickly without using salt?

One of the best ways to melt ice quickly without using salt is by using hot water. Simply pour hot water over the ice and it will melt almost instantly. However, be careful not to use boiling water as it can cause damage to the surface underneath the ice.

2. Can I use household items to melt ice quickly?

Yes, there are several household items that can be used to melt ice quickly. These include rubbing alcohol, vinegar, and sugar. Simply mix these items with warm water and pour over the ice to melt it.

3. What is the most effective way to melt ice quickly on a large surface area?

The most effective way to melt ice quickly on a large surface area is by using a de-icing solution. These solutions are specifically designed to melt ice quickly and can cover a large area with just one application.

4. How long does it take for ice to melt using different methods?

The time it takes for ice to melt using different methods can vary depending on the size and thickness of the ice, as well as the temperature and method used. Generally, hot water can melt ice in a matter of seconds, while household items and de-icing solutions may take a few minutes.

5. Is it safe to use chemicals to melt ice quickly?

While chemicals such as salt and de-icing solutions can effectively melt ice quickly, they can also be harmful to the environment and surrounding plants and animals. It is important to use these chemicals sparingly and follow proper disposal guidelines to minimize their impact.

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