How Long Does It Take Ice To Freeze?

A watched ice tray never freezes. Okay, that’s not true. But sometimes it feels like forever, especially if you need ice cubes RIGHT NOW. So what’s going on? Why isn’t water freezing faster? How long does it take for ice cubes to freeze? Under standard conditions, say your freezer, a simple 12-cube plastic tray will take around four hours from soaked to solid.

Actually, it’s pretty fun to play around with partially frozen cubes.
Give it a try! Some of the water is still liquid inside the cube, while the outside is frozen solid.
What about an ice machine? Well, the time it takes for ice to freeze can get a bit more complex.
The size of your cube, chip, pearl, whichever ice you enjoy, directly relates to the speed at which it freezes.

The smaller the amount of water is, the faster it’ll freeze. We wrote a blog about directional freezing using a normal picnic coole r, You need to fill it up with water, store it in a freezer, and wait. Patiently. That will take you anywhere between a few hours to an entire day.

That’s because ice freezes from the outside in.
More water means more to freeze.
Thanks to molecular physics and the property of water, that just takes longer.
That’s why ice trays have dividers.
Big machines have this too! Reducing the surface area of water drastically increases the time to freeze.
The interior temperature of your freezer matters.

And you wouldn’t think it at first, but so does the exterior temperature. Ice machines and refrigerators need optimal temperatures to function at peak efficiency. Reduced efficiency means longer freeze times or worse, damage. Warmer temperatures will increase the freezing time of your ice, and if it climbs above 32 degrees Fahrenheit, or zero degrees celsius, it’ll begin to melt.

Can ice freeze in 2 hours?

How Long Will It Take for My Ice Cubes to Freeze? Answers to All Your Ice-Making Questions Mar 04, 2019 Whether you’re hosting a party or just trying to chill after a long week of work, there’s almost nothing more disappointing than opening the freezer to find empty ice cube trays,

Now what? That glass of premium Scotch or iced coffee isn’t going to cool itself, and you’re left with the prospect of heading to the nearest gas station for a bag of ice or filling up the trays and waiting.
But how long will it take for those ice cubes to freeze? Ice-making is a surprisingly complex subject, even though you’ve no doubt been doing it your whole life.

Still, there are a remarkable number of factors that affect the speed at which your ice freezes and the quality of the ice cubes you get when the process is complete. Here’s what you need to know about the speed at which ice freezes. In most situations, ice made in a standard ice tray — those plastic models with space for a dozen tapered cubes — takes about three to four hours to freeze in your home freezer.

Water freezes when it reaches 32 degrees Fahrenheit (0 degree Celsius), but the time it takes to do so depends on several factors that may be different in your freezer than in your neighbor’s.
First, the size of the ice cubes matters.
If you have an unusual ice tray designed to make very small ice cubes, these will freeze faster than large blocks of ice.

The surface area of the ice will also affect freezing time, since ice begins to freeze from the outside in. This means that an ice tray that has air space between each cube will freeze faster than one that merely has dividers. Second, the air temperature of your freezer matters.

Most home freezers are set at 0 degrees Fahrenheit, which is optimal. However, if you leave your freezer open or fill it with room-temperature food at the same time you make your ice, you’ll unwittingly raise the air temperature in the freezer, which will slow down your ice making process. For starters, make sure that you keep your freezer at the recommended temperature and keep it closed as much as possible — that means no checking on it for at least three hours.

If you’re really in a rush, you can try temporarily lowering the temperature of your freezer, which will help chill the water molecules faster. You can also instead of a plastic or silicone one. Metal is a very poor insulator, so the water will cool down more quickly.

Finally, you might also try the world’s most counterintuitive trick: Use hot water to fill your ice cube trays, This method relies on the Mpemba effect to get your ice to freeze faster than it would if you used cold water in your ice trays, is a bit of a paradox. Though Aristotle and other philosophers long claimed that hot water freezes faster than cold, it wasn’t until the 1960s that a Tanzanian high school student named Erasto Mpemba began experimenting with the phenomenon in earnest.

Mpemba noticed that when he made ice cream with hot milk, it froze faster than chilled milk. He asked his teacher about it, but his teacher didn’t believe him. Mpemba then tried experiments using warm water to make ice, and scientists replicated them. They discovered that, in many cases, warmer water does freeze faster than cool water,

This fact is now called the Mpemba effect after a high school kid who was determined to prove his teacher wrong. There are several possibilities for why the Mpemba effect works in any given situation. Ice is complicated, and it’s hard to know exactly which reason — or combination of reasons — is responsible for the Mpemba effect in any given situation.

Here are some of the theories scientists have come up with to explain why ” hot ice ” freezes faster:

• Evaporation: Warm water evaporates more quickly than cool water, which leaves behind less water to freeze. Since the resulting ice cubes are slightly smaller, they freeze more quickly. • Released Gases: When tap water is boiled, gases and minerals in it are released into the air, which could slightly raise the freezing point and allow the ice to freeze solid more quickly than unboiled water. By this theory, distilled water may also freeze slightly faster than tap. • Convection: As the hot water cools, the difference in temperature between the cold surface and the hot bottom of the ice cube tray will cause a faster rate of cooling due to convection (the movement of heat through the fluid). • Covalent Bonds : A looked at this issue at a molecular level and discovered that heating shortens the bond between the hydrogen atoms and oxygen atoms in individual water molecules, which lets heat escape the water at a faster rate. This means that hot water will freeze faster than cold water,

Maybe. Most of these freeze water that’s pumped into a freezer tray in the freezer, which isn’t really any faster than putting water in your plastic freezer trays yourself — it’s just more convenient because the machine remembers to refill the trays for you.

On the other hand, some built-in ice makers are designed with refrigerant coils that directly chill the ice trays, freezing water much faster than relying solely on cold air. This type of ice maker is usually located in a side-by-side refrigerator/freezer, on the fridge side of the appliance. Yes. Countertop ice makers function more like large commercial ice machines than built-in fridge or freezer ice makers.

This is because the that pump refrigerant directly to the ice tray, This is similar to the direct-freeze type of ice makers described above. However, the ice trays in dedicated ice makers aren’t filled with water, but rather have water run over the super-cold metal.

Ice crystals form instantly on the trays and build up as the water cascades over them. This is much faster than having water sit in a cup and waiting for it to freeze, because the center of an ice cube is warm and takes longer to freeze. As a bonus, the cascading water that slowly builds up to make ice is a great way to get crystal clear ice for cocktails and other cold drinks,

This is because standard ice cubes freeze from the outside in, which pushes minerals and gases toward the center, where they are trapped in an unattractive white cloud. Because the cascading water doesn’t allow for impurities to be trapped, you get purer, prettier ice.

When you’re looking for a dedicated ice maker for your home, you definitely don’t have to install a large commercial model! is just 16 inches tall, which is small enough to slide under upper cabinets in a corner of your kitchen workspace. Despite its small size, this ice maker is powerful enough to make up to 50 pounds of ice each day.

That means it churns out ice at a much faster clip than any in- refrigerator ice maker can, and you only need to fill up the reservoir once or twice rather than dealing with ice cube trays all day long. If you need to serve drinks to a crowd, this is definitely the way to go to make sure you stay fully stocked. For reliably fast and plentiful ice, a dedicated ice maker is the way to go. Countertop models are less expensive than you think, and they’re a great investment in convenience if you love to entertain or need a large store of ice for projects like making homemade ice cream or packing a cooler for camping or fishing.

If you plan to stick with your typical freezer ice cube trays but need ice fast, turn down the temperature on your freezer and try filling your trays with boiling water to take advantage of the Mpemba effect, For a more long-term solution for making ice cubes fast, invest in metal ice cube trays or trays designed to make smaller ice cubes or water bottle ice rods with lots of surface area.

Both of these types of ice should freeze up faster than standard cubes. Now that you know some of the science behind how ice freezes and the factors that can speed it up or slow it down, you can make an informed decision about the best way to get ice quickly when you need it most.

Can ice freeze in 3 hours?

What Is Ice? – Ice is a form of solid water that occurs naturally when temperatures drop below the freezing point. It’s made up of frozen crystals, which can vary in size and shape depending on the conditions in which it forms. Ice has many uses, from being used as a cooling agent to providing a surface for recreation activities.

Does warm ice freeze faster?

From Wikipedia, the free encyclopedia Temperature vs time plots, showing the Mpemba Effect. The Mpemba effect is the name given to the observation that a liquid (typically water ) which is initially hot can freeze faster than the same liquid which begins cold, under otherwise similar conditions.

Does hot water make ice freeze faster?

Yes—a general explanation – Hot water can in fact freeze faster than cold water for a wide range of experimental conditions. This phenomenon is extremely counterintuitive, and surprising even to most scientists, but it is in fact real. It has been seen and studied in numerous experiments,

Although this phenomenon has been known for centuries, and was described by Aristotle, Bacon, and Descartes, it was not introduced to the modern scientific community until 1969, by a Tanzanian high school pupil named Mpemba. Both the early scientific history of this effect, and the story of Mpemba’s rediscovery of it, are interesting in their own right — Mpemba’s story in particular providing a dramatic parable against making snap judgements about what is impossible.

This is described separately below. The phenomenon that hot water may freeze faster than cold is often called the Mpemba effect. Because, no doubt, most readers are extremely skeptical at this point, we should begin by stating precisely what we mean by the Mpemba effect.

We start with two containers of water, which are identical in shape, and which hold identical amounts of water. The only difference between the two is that the water in one is at a higher (uniform) temperature than the water in the other. Now we cool both containers, using the exact same cooling process for each container.

Under some conditions the initially warmer water will freeze first. If this occurs, we have seen the Mpemba effect. Of course, the initially warmer water will not freeze before the initially cooler water for all initial conditions. If the hot water starts at 99.9°C, and the cold water at 0.01°C, then clearly under those circumstances, the initially cooler water will freeze first.

But under some conditions the initially warmer water will freeze first: if that happens, you have seen the Mpemba effect. But you will not see the Mpemba effect for just any initial temperatures, container shapes, or cooling conditions. This seems impossible, right? Many sharp readers may have already come up with a common proof that the Mpemba effect is impossible.

The proof usually goes something like this. Say that the initially cooler water starts at 30°C and takes 10 minutes to freeze, while the initially warmer water starts out at 70°C. Now the initially warmer water has to spend some time cooling to get to get down to 30°C, and after that, it’s going to take 10 more minutes to freeze.

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So since the initially warmer water has to do everything that the initially cooler water has to do, plus a little more, it will take at least a little longer, right? What can be wrong with this proof? What’s wrong with this proof is that it implicitly assumes that the water is characterized solely by a single number — its average temperature.

But if other factors besides the average temperature are important, then when the initially warmer water has cooled to an average temperature of 30°C, it may look very different than the initially cooler water (at a uniform 30°C) did at the start. Why? Because the water may have changed when it cooled down from a uniform 70°C to an average 30°C.

It could have less mass, less dissolved gas, or convection currents producing a non-uniform temperature distribution. Or it could have changed the environment around the container in the refrigerator. All four of these changes are conceivably important, and each will be considered separately below. So the impossibility proof given above doesn’t work.

And in fact the Mpemba effect has been observed in a number of controlled experiments It is still not known exactly why this happens. A number of possible explanations for the effect have been proposed, but so far the experiments do not show clearly which, if any, of the proposed mechanisms is the most important one.

While you will often hear confident claims that X is the cause of the Mpemba effect, such claims are usually based on guesswork, or on looking at the evidence in only a few papers and ignoring the rest.
Of course, there is nothing wrong with informed theoretical guesswork or being selective in which experimental results you trust; the problem is that different people make different claims as to what X is.

Why hasn’t modern science answered this seemingly simple question about cooling water? The main problem is that the time it takes water to freeze is highly sensitive to a number of details in the experimental setup, such as the shape and size of the container, the shape and size of the refrigeration unit, the gas and impurity content of the water, how the time of freezing is defined, and so on.

Because of this sensitivity, while experiments have generally agreed that the Mpemba effect occurs, they disagree over the conditions under which it occurs, and thus about why it occurs. As Firth wrote “There is a wealth of experimental variation in the problem so that any laboratory undertaking such investigations is guaranteed different results from all others.” So with the limited number of experiments done, often under very different conditions, none of the proposed mechanisms can be confidently proclaimed as “the” mechanism.

Above we described four ways in which the initially warmer water could have changed upon cooling to the initial temperature of the initially cooler water. What follows below is a short description of the four related mechanisms that have been suggested to explain the Mpemba effect.

Evaporation — As the initially warmer water cools to the initial temperature of the initially cooler water, it may lose significant amounts of water to evaporation. The reduced mass will make it easier for the water to cool and freeze. Then the initially warmer water can freeze before the initially cooler water, but will make less ice. Theoretical calculations have shown that evaporation can explain the Mpemba effect if you assume that the water loses heat solely through evaporation, This explanation is solid, intuitive, and evaporation is undoubtedly important in most situations. But it is not the only mechanism. Evaporation cannot explain experiments that were done in closed containers, where no mass was lost to evaporation, And many scientists have claimed that evaporation alone is insufficient to explain their results,
Dissolved Gasses — Hot water can hold less dissolved gas than cold water, and large amounts of gas escape upon boiling. So the initially warmer water may have less dissolved gas than the initially cooler water. It has been speculated that this changes the properties of the water in some way, perhaps making it easier to develop convection currents (and thus making it easier to cool), or decreasing the amount of heat required to freeze a unit mass of water, or changing the boiling point. There are some experiments that favor this explanation, but no supporting theoretical calculations.
Convection — As the water cools it will eventually develop convection currents and a non-uniform temperature distribution. At most temperatures, density decreases with increasing temperature, and so the surface of the water will be warmer than the bottom: this has been called a “hot top.” Now if the water loses heat primarily through the surface, then water with a “hot top” will lose heat faster than we would expect based on its average temperature. When the initially warmer water has cooled to an average temperature the same as the initial temperature of the initially cooler water, it will have a “hot top”, and thus its rate of cooling will be faster than the rate of cooling of the initially cooler water at the same average temperature. Got all that? You might want to read this paragraph again, paying careful distinction to the difference between initial temperature, average temperature, and temperature. While experiments have seen the “hot top”, and related convection currents, it is unknown whether convection can by itself explain the Mpemba effect.
Surroundings — A final difference between the cooling of the two containers relates not to the water itself, but to the surrounding environment. The initially warmer water may change the environment around it in some complex fashion, and thus affect the cooling process. For example, if the container is sitting on a layer of frost which conducts heat poorly, the hot water may melt that layer of frost, and thus establish a better cooling system in the long run. Obviously explanations like this are not very general, since most experiments are not done with containers sitting on layers of frost.

Finally, supercooling may be important to the effect. Supercooling occurs when the water freezes not at 0°C, but at some lower temperature. One experiment found that its initially hot water supercooled less than its initially cold water. This would mean that the initially warmer water might freeze first because it would freeze at a higher temperature than the initially cooler water.

If true, this would not fully explain the Mpemba effect, because we would still need to explain why initially warmer water supercools less than initially cooler water.
In short, hot water does freeze sooner than cold water under a wide range of circumstances.
It is not impossible, and has been seen to occur in a number of experiments.

But despite claims often made by one source or another, there is no well-agreed explanation for how this phenomenon occurs. Different mechanisms have been proposed, but the experimental evidence is inconclusive. For those wishing to read more on the subject, Jearl Walker’s article in Scientific American is very readable and has suggestions on how to do home experiments on the Mpemba effect, while the articles by Auerbach and Wojciechowski are two of the more modern papers on the effect.

How do you make ice in a hurry?

How To Make Ice Cubes Faster (And The Weird Science Behind It!) One of the best perks of being a blogger is that I always have someone to share interesting information with. (Of course I’m referring to you, my wonderful readers!) And I recently learned about a fascinating phenomenon that I instantly wanted to share with you! It may not be something you end up using every day, but it could be very useful in a pinch. The next time you need in a hurry, try filling your ice cube tray with hot water rather than cold water. Due to a mysterious little phenomenon called the Mpemba effect (pronounced mem-PEM-ba), hot water is capable of freezing faster than colder water under the same conditions. It sounds backward, and maybe even a little crazy, but it really works!

Does salt make ice freeze faster?

Have You Ever Wondered. –

Does salt water freeze? At what temperature does ocean water freeze? Is polar ice freshwater or salt water?

Today’s Wonder of the Day was inspired by Drusilla. Drusilla Wonders, ” does salt water freeze ” Thanks for WONDERing with us, Drusilla! Isn’t ice WONDERful? On a hot day, nothing goes down quite as well as lemonade poured over a glass full of ice cubes.

In fact, ice makes so many things better. For example, we love to use ice to make homemade ice cream ! When Old Man Winter comes calling, falling temperatures can turn creeks, lakes, ponds, and even rivers into frozen rinks you can skate on. But what about the ocean ? If you’ve ever been to the ocean in the winter, you’ve probably noticed that it doesn’t freeze like a small pond might.

So does the ocean ever freeze ? If you’ve seen pictures of the North Pole or the South Pole, you know that there are polar ice caps in those places. If the ocean freezes in those areas, why doesn’t the rest of the ocean freeze during the winter? The freezing point of freshwater is 0° Celsius or 32° Fahrenheit.

The presence of salt in water, though, reduces the freezing point of water, The more salt in the water, the lower the freezing point will be. When freshwater freezes, water molecules of hydrogen and oxygen have bonded together into a crystalline structure of ice, The presence of salt makes it harder for water molecules to bond to the ice structure, because ice naturally repels salt molecules.

So in a sense, the salt gets in the way of water molecules, blocking them from joining the ice, The salt also bumps into the ice, knocking water molecules off of the structure – and that’s how salt melts ice, When salt molecules displace water molecules, the freezing rate slows down.

This is why salt is often used on icy roads to slow down freezing and make them safer to travel upon. Although the saltiness of ocean water varies, often ocean water has about 35 grams of salt for every 1,000 units of water, This lowers the freezing point of ocean water to about -1.8° C or 28.8° F. So ocean water will freeze,

It just needs to reach a lower temperature, Another factor that affects the freezing of ocean water is its movement, Unlike ponds, ocean waves move around constantly. This helps ocean water retain heat. As a result, only really cold areas, such as the North Pole or South Pole, usually get cold enough for ocean water to freeze,

Will water freeze in 5 hours?

How Long Does It Take For A Bottle Of Water To Freeze? – Looking to freeze water in a bottle rather than ice trays? If so, you’ll be looking at around four to five hours for the water to freeze completely inside the bottle, The size of the bottle can determine this timespan, but a standard-sized bottle should fully freeze within five hours.

The interior temperature of a freezer typically sits at 32 degrees Fahrenheit, making it ideal conditions for water to freeze. But, water outside will nearly always freeze at different rates. The freezing point for water is generally considered to be 32 degrees Fahrenheit (zero degrees Celsius). Once temperatures begin to fall below this, water will start to turn to ice.

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During this process, heat is released, allowing the water to turn into a solid form. If you were to place a water bottle outside in a temperature under 32 degrees Fahrenheit, it should freeze in around five hours. But, the temperature must maintain this freezing state.

Can it be too cold for ice?

Can it ever be too cold to snow? | Notes and Queries | guardian.co.uk

Can it ever be too cold to snow?
Sandra, Sydney Australia

Yes. Clouds will not release their moisture unless encouraged to do so. This is generally when warm air rising from the earth causes the clouds to rise on thermals, but in order to do so they must lose weight – they release their moisture, which falls either as rain or snow. If the ground is too cold, then the clouds don’t rise, so no snow or rain.
2. Tony James, London England

It is unlikely that it could be too cold to snow if there was sufficient humidity in the atmosphere. But a very cold atmosphere would hold little water and would therefore be quickly ‘snowed out’ In very arid climates such as the (ant)arctic, temperatures are so low that little evaporation of water from land or water occurs and therefore there is little humidity generated. Atmospheric circulation adds to this by creating decending air (high pressure) over the coldest parts of the earth (the poles) which does not aid the transmission of water vapour to higher altitudeds which would normally generate precipitation due to lapse rates. Rare, very cold, dry British weather may often be attributed to an arctic (high pressure) system moving over the UK from the north/ north east. In continental climates such as Siberia or Canada, large blocking highs may create long periods of cold dry weather. Our weather is dominated by maritime systems which are unstable and relatively warm and wet, this is why we rarely have true wintery weather, but frequent snow flurries etc in winter.
- GACM, UK

Strictly speaking, no. But it can be too dry to snow, and the colder air is, the dryer it tends to be because cold air holds less water vapour than warmer air. At minus 15 Celsius, air’s capacity to hold moisture is only 25 percent that of air at the freezing point. Even the coldest air can hold some moisture, though, so there is no theoretical point below which it is too cold to snow, but the colder the air, the less likely that ice crystals will precipitate out and form into flakes to fall to earth as snow. Major snow storms at very low temperatures (below, say, minus 20 Celsius) are rather rare.
2. William Dunlap, Hamden, Connecticut USA

Strictly speaking, no. But it can be too dry to snow, and the colder air is, the dryer it tends to be because cold air holds less water vapour than warmer air. At minus 15 Celsius, air’s capacity to hold moisture is only 25% that of air at the freezing point. Even the coldest air can hold some moisture, though, so there is no theoretical point below which it is too cold to snow, but the colder the air, the less likely that ice crystals will precipitate out and form into flakes to fall to earth as snow. Major snow storms at extremely low temperatures (below, say, minus 20 Celsius) are rather rare.
- William Dunlap, Hamden, Connecticut

No. Only if the teperature falls to absolute zero, approx -500% f, 275% c, there will always be a possibility of snow depending on too many variables to be mentioned.
2. bill, liverpool uk

: Can it ever be too cold to snow? | Notes and Queries | guardian.co.uk

How long is safe to ice?

Summary – Ice helps reduce the pain and swelling of an injury. You can ice an injury a few times a day, but avoid keeping the ice on for more than 20 minutes at once. When the injury feels numb, remove the ice. Ice can help your injury feel better, but it may not be necessary for healing.

What happens to the ice after 10 minutes?

WHEN ICE IS PLACED UNDER THE SUN FOR 10 MINUTES IT WILL MELTS AS DUE TO INCREASE IN TEMPERATURE AND KINETIC ENERGY OF PARTICLES.

Can water freeze in 4 hours?

How long it takes for water to freeze at different temperatures –

Water can freeze at many different temperatures, depending on the environment and conditions.
At 32°F, it can take anywhere from six to thirteen hours for water to freeze, while at 26°F a more typical freezing time is in the range of four to six hours.
In places that regularly get below -20°C (about -4°F) like Antarctica, it may only take minutes for large bodies of water to solidify into ice.

A warmer environment like a place with temperatures often rising above 0°C could lead to a much longer freezing process than usual; sometimes taking up to several days. Although there are variations due to specific circumstances and conditions, understanding how long it takes for water to freeze in different settings can provide information about the climate and temperature of an area.

What freezing method is the fastest?

Cryogenic freezing – Cryogenic freezing is the fastest IQF freezing method on the market. In cryofreezing, the items are sprayed or immersed directly in liquid nitrogen or carbon dioxide and frozen almost instantly. The method prevents the formation of macro crystals – which is preferable, as large ice crystals rupture the food’s cell membranes and cause fluid loss.

The lack of macro crystals results in the highest product quality of frozen and chilled food that sustains its natural nutritional value, taste, and shape.
Cryogenic freezing is relevant for industries where food safety and food quality is of the essence, and it is widely used among manufacturers that add high value to their products.

Examples are special baked goods, seafood, meat, poultry, and dairy products. It is also relevant in nonfood industries, such as pharma and metal. We recommend cryogenic freezing for new production lines, seasonal production, or small and medium productions of high-quality food.

The investment in a cryogenic freezing solution is 2.5 times lower than in a mechanical solution, the initial start-up costs and operating costs are lower, dimensions are smaller, and cryogenic equipment is always ready to use and easy and fast to clean.
However, as production grows, the operational costs of cryogenic freezing will exceed the costs of running a mechanical solution.

Want to know more about individual quick freezing (IQF)? Individual quick freezing Customized solutions

Why does ice take so long to freeze?

Actually, it’s pretty fun to play around with partially frozen cubes.
Give it a try! Some of the water is still liquid inside the cube, while the outside is frozen solid.
What about an ice machine? Well, the time it takes for ice to freeze can get a bit more complex.
The size of your cube, chip, pearl, whichever ice you enjoy, directly relates to the speed at which it freezes.

That’s because ice freezes from the outside in. More water means more to freeze. Thanks to molecular physics and the property of water, that just takes longer. That’s why ice trays have dividers. Big machines have this too! Reducing the surface area of water drastically increases the time to freeze. The interior temperature of your freezer matters.

Why does cold water taste better?

Ice Suppresses the Flavor of the Beverage It’s In – Researchers believe most people prefer to drink ice water because it’s less flavorful than room temperature water. That might sound counterintuitive, but warm water (especially warm unfiltered water) tends to taste sweeter and more acidic. Cold water, on the other hand, suppresses the sensitivity of our taste buds and quells any impurities that make the water taste slightly different.

Why does boiled water freeze faster?

Introduction – Space was limited in the students’ refrigerator, and in the rush to nab the last available ice tray, Mpemba opted to skip waiting for his boiled-milk-and-sugar concoction to cool to room temperature like the other students had done. An hour and a half later, his mixture had frozen into ice cream, whereas those of his more patient classmates remained a thick liquid slurry.

When Mpemba asked his physics teacher why this occurred, he was told, “You were confused. That cannot happen.” Later, Osborne came to visit Mpemba’s high school physics class. He recalled the teenager raising his hand and asking, “If you take two beakers with equal volumes of water, one at 35°C and the other at 100°C, and put them into a refrigerator, the one that started at 100°C freezes first.

Why?” Intrigued, Osborne invited Mpemba to the University College in Dar es Salaam, where they worked with a technician and found evidence for the effect that bears Mpemba’s name. Still, Osborne concluded that the tests were crude and more sophisticated experiments would be needed to figure out what might be going on.

Over the decades, scientists have offered a wide variety of theoretical explanations to explain the Mpemba effect.
Water is a strange substance, less dense when solid than liquid, and with solid and liquid phases that can coexist at the same temperature.
Some have suggested that heating water might destroy the loose network of weak polar hydrogen bonds between water molecules in a sample, increasing its disorder, which then lowers the amount of energy it takes to cool the sample.

A more mundane explanation is that hot water evaporates faster than cold, decreasing its volume and thus the time it takes to freeze. Cold water also could contain more dissolved gases, which lower its freezing point. Or perhaps external factors come into play: A layer of frost in a freezer can act as an insulator, keeping heat from leaking out of a cold cup, whereas a hot cup will melt the frost and cool faster.

Those explanations all assume that the effect is real — that hot water really does freeze faster than cold.
But not everyone is convinced.
In 2016, physicist Henry Burridge of Imperial College London and mathematician Paul Linden of the University of Cambridge did an experiment that showed how sensitive the effect is to the particulars of measurement.

They speculated that hot water might form some ice crystals first but take longer to fully freeze. Both of these events are difficult to measure, so Burridge and Linden instead noted how long it took water to reach zero degrees Celsius. They found that the readings depended on where they placed the thermometer.

If they compared the temperatures between hot and cold cups at the same height, the Mpemba effect didn’t appear.
But if measurements were off by even a centimeter, they could produce false evidence of the Mpemba effect.
Surveying the literature, Burridge and Linden found that only Mpemba and Osborne, in their classic study, saw a Mpemba effect too pronounced to attribute to this kind of measurement error.

The findings “highlight how sensitive these experiments are even when you don’t include the freezing process,” said Burridge.

Is it better to make ice with hot or cold water?

Why hot water freezes faster. – When water is frozen, a similar reaction happens. The molecules initially tighten up and bind together to create a solid form. Since hot water’s molecules are already tightened up, it has a head start on looking it should in its frozen state.

How do you make ice cubes in 30 minutes?

13 July 2022, 12:21 This hack could be a game-changer. (stock images). Picture: Getty Ever forgotten to get your ice cubes ready in time for the BBQ? This simple hack could get them frozen in record time. As the UK heatwave continues, many of us will be spending increasing amounts of time in the garden enjoying the sunshine.

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This hack could help rescue your BBQs this summer. (stock image). Picture: Getty Sharing a video of the hack to Tik Tok, she said: “Why did no one f****** tell me that this s*** was a thing.” She then filmed herself with two ice cube trays and two bottles of water (which are labelled hot and cold).

After pouring the water into each tray, she puts them in the freezer for 30 minutes – and then reveals that the ice cube tray filled with hot water is frozen solid. **Warning: video contains swearing** The science behind the hack is called the ‘Mpemba effect’, which, according to Science Daily, is a “counter-intuitive physical phenomenon revealed when hot water freezes faster than cold water.” Many shocked Tik Tok users rushed to comment their excitement about the hack, with one writing: “If this is true ur life will change forever.

” Another joked: “I’m boiling my beer before I put it inside the fridge.”

How fast does ice freeze at 15 degrees?

Ice Growth: Thin to Thick Summary: There are a couple of pretty good methods for predicting ice growth. One was developed by George Ashton in 1989 and is based on freezing degree days. It is a good, general purpose method when you do not have a good feel for the conditions other than temperature.

The second method is the Swedish method has been developed by Martin Ajne (and others?).
It uses a combination of air temperature, wind speed and radiational cooling.
It is most accurate for thin ice (up to a couple inches).
It is handy for guessing how much ice will form over night or in the next day or two.

It is described near the end of this page. The Ashton Ice Growth Prediction Method Once the first layer of ice catches on a lake it grows thicker at rate that is dependent on air temperature, windiness, radiational cooling, the thickness of the ice sheet and any snow or frost buildup on the ice sheet.

Temperature is the easiest to assess.
Freezing degree days (FDD) are the average number of degrees below freezing over 24 hours.
For example is the average temperature over a day is 17 degrees that day had fifteen FDDs.
An ice sheet will, in theory, grow at a rate of roughly one inch per fifteen FDDs starting from ice between 1/2″ and 3″ thick (as the ice gets thicker the growth rate decreases as a result of the thermal resistance of the thicker ice).

This is based on there being a bit of wind, a reasonably clear sky and no snow/frost on the ice. If there is no wind or there are cloudy skies, the ice growth may be considerably slower. For example, starting from 2″ ice, if the maximum temperature yesterday was 22 degrees and the minimum overnight was 12 degrees the average is 17 deg giving 15 FDDs for the 24 hour period. 27 mm(1.06″) ice: Not quite enough to stay on top. It needs another 1 mm to barely support 175 lb. To have a reasonable safety factor it needs another 20 or 30 freezing-degree-days to make it thick enough. For an ice sheet to grow thicker it has to dissipate 80 calories per gram of water that turns to ice.

The heat has to get out of the ice sheet either by conduction and convection into overlying air or by radiational cooling from the ice surface.
In general, when the ice is thinner than 3″ the cooling rate is limited by the ability of the air over the ice to transmit heat.
Thin ice at temperatures near freezing thickens most quickly when radiaional cooling conditions are best (clear sky, low humidity).

Note: Ice thickness is not the only thing that matters with bearing strength. With cold (fully frozen) ice, thickness pretty much tells the story with strength. Thawed ice can be anywhere from a little weaker to much weaker than cold ice. Catching: Before the ice can get thick it has to ‘catch’, forming the primary ice layer that grows into something we can skate, fish, sail and drive on.

There several conditions that support ice catching: The bulk water water needs to be cool enough (typically in the 35-37 degree range). Cooling of the bulk water correlates with the water depth. Winds in the low single numbers for a few hours is often what allows a new ice sheet to form and survive. See: Ice physics for recreational ice-users for more on this and many other aspects of ice growth.

Once the bulk temperature gets to 39 degrees or colder (maximum density) it is convectivley stable if there is no wind to mix the water. The water surface cools from radiational cooling, cold air with light wind. The lake is most likely to form ice when winds are light which is also when the air temperature is colder and skies are clear.

In this circumstance radiational cooling accounts for most of the ice growth.
A clear sky allows radiation to remove energy from the surface at a rate of about 70 watts/square meter.
This helps establish a thin, supercooled layer that typically starts to form ice at about half a degree (F) of supercooling.

For the first crystals to form on the supercooled surface layer something needs to nucleate them. Ice is the best nucleating agent for this. Examples include snow, and ice fog. Lake water is also full of fine sediment, bacteria and other things that can act as nucleating agents. The following graphs are based on a formula proposed George Ashton in 1989. It covers both thin and thick ice. The 100+ year old Stephan solution works well with an adjustment coefficient of 0.5 to 0.8 for thicker ice or very cold conditions but dramatically overestimates the growth rate of thin ice and less severe temperatures.

The Stephan solution does not factor in the heat transfer capacity of the air over the ice sheet but the Ashton formula does. Neither directly factors in radiational cooling, solar heating, wind, snowcover and other factors that can affect ice growth rates however by using adjustment coefficients they approximate the effect of some of these factors.

The following charts show calculated growth rates for different periods of time. This can be handy for making a rough guess of growth over time at a constant temperature. As always, actual measurements of thickness trump calculated numbers. Reality is more complicated. The temperature is rarely constant for more than a few hours. Radiational cooling on a clear night can be the major part of the cooling effect (thin ice grows at above freezing temperatures in this situation). Sun angle is a big factor as is the presence or lack of sun, especially later in the season.

Cold wind increases heat removal from the top of the ice. Snow is a very effective insulator and it dramatically slows growth. Slush on the surface or as a layer within the ice sheet (layered ice) stops growth on the bottom of the ice sheet until the slush layer is fully frozen. These graphs are of most practical use to determine how much an ice sheet is likely to grow in a day or two of fairly constant temperatures.

For example if you have bare ice that 2″ thick and it is going to average 10 degrees for the next two full days, the ice will probably grow to about 5″ in that time. As with everything else about ice, make sure you measure what the ground truth is (and don’t use your truck as your testing tool).

There are lots of reasons it could have grown less than expected and not many that it might have allowed it to grow more.
Related to this, the temperature data for several of the 2013 season fatalities shows they were preceded by several days of temperatures that held near freezing.
Many important details about the incidents are not known but it does appear likely that ice in these circumstances may slowly thaw.

Thawing is, on average, about 30% faster than growth which is probably part of this story. The following graph from Ashton’s paper Thin Ice Growth shows reality against the calculated estimate. The upper three lines are the Stephan Solution with adjustment factors of 0.5, 0.7 and 1.0.

The lower three lines are for the Ashton approach with the lines representing different values of the bulk heat transfer coefficient from ice top surface to air well above the ice (H ia ), I used a value of H ia of 20 in making the graphs shown above as that best represents the empirical data. This is based on conditions similar to the St Lawrence River.

If the area you are interested in is less windy, expect slower ice growth. (December-January winds on the St Lawrence River average about 9 mph with average gusts at 22). Most of the data falls within a factor of 2 the predicted value at H ia =20. The extreme cases at low thicknesses (1/4″ thick, red arrow) that freeze faster than the average by nearly 10 times. This may well be a situation where the temperature is slightly below freezing and radiaitional cooling is the main cooling mechanism.

The blue arrows point to growth rates that are slower than typical. Sunny weather, calm winds, cloudy skies or snow are possible contributors to this. The Swedish Ice Growth Prediction Method: For a more nuanced look at growth of thin ice (less than a couple of inches) have a look at Marten Ajne’s book Ice Physics for Recreational Ice-Users,

It gives the following rules of thumb for thin ice growth in snow free conditions: The sum of:

0.05mm/h for every negative degree (C) of air temperature
0.02 mm/hr for times the product of wind speed (m/s) and negative air temperature
0.7 mm/hr for 100% clear skies and nothing for completely clouded.

For example if the temperature is 32 degrees F, there is no wind and the sky is clear about 1/3 of an inch will form overnight (12 hours) as a result of radiational cooling alone. If the sky is cloudy and calm the temperature will have to be about 7 degrees (F) to grow 1/3″ of ice in 12 hours.

If it is cloudy and there is a 10 mph wind the temperature will have to be 27 degrees F to grow 1/3″ of ice in 12 hours. This assumes there is a layer of ice on the water that is thick enough to fend off the 10 mph wind. If you have clear skys, cold temperatures (15 deg F) and wind (15 mph) this method predicts about 1.8″ of ice will grow in 12 hours.

Both the Ashton and Ajne approaches are easiest to use if you put the algorithms in a spreadsheet. Click here for a spreadsheet set up for the Ajne approach (in,ods format-OpenOffice). Click here for an Excel (,xls) version More Information For a more substantial discussion of this and other dynamic processes on ice I highly recommend a copy of Ice physics for recreational ice-users by Mårten Ajne,

If you have read this far in this article you should have a copy of his book.
Click Here for a bit more insight into the role of different factors on thin ice growth from Marten Ajne.
Click here to see George Ashton’s paper: Thin Ice Growth,
It was published in WATER RESOURCES RESEARCH,VOL.25, No 3, Pages 564-566, March 1989.

For a look at Jan-Erik Gustafsson’s forecast method skating ice, see the January 24, 2012 Blog entry or go directly to his North American Forecast Site, Reference to a paper on radar ice thickness in Canada Click here for more info on bearing strength.

How fast can you freeze at?

Frostbite: the cold, hard facts | CBC News Once the wind chill makes the temperature feel like –28 or colder, exposed skin can freeze in under 30 minutes. When it drops to –40, frostbite can occur in less than 10 minutes. Take it to –55, and you’re in danger within two minutes.

Will ice melt at 30?

Snow is a piece of fancy-looking ice that drops in small pieces but accumulates into a larger form when it settles. Water changes states at 0°C or 32°F, and ice is the solid state of water. The snow will melt above 32° or freeze below 32° as a result of this.