Ice is the solid state of water, and is thus the form of water to be expected at lower temperatures. Other forms of water include the gaseous form of water – steam – and the liquid form of water, which is known as... water.

How is Ice Used?

Ice can be used in many different ways, whether it be for science or for our personal enjoyment. While many areas of civilisation need ice, many others must contend with it.

Food and Drink

• Drinks

  Ice, being quite cold (compared to the average global temperature of 9°C) is often used to cool drinks. Indeed one very early use of ice was to cool drinks in warm weather. Today almost any fizzy soft drink comes with the offer of ice, and in hotter countries most drinks will be cooled using ice cubes. Meanwhile, any order of white wine in a fancy restaurant will prompt the arrival of an ice bucket to chill the bottle.

• Puddings

  Ice is used in a whole range of puddings, either for its cooling capability or as a base for flavours. Some of these recipes are simplicity itself, such as using snow mixed with berry juice¹ to create a snow cone. These are very common in America, but variants have been known for centuries in the Far East and civilisations around the Mediterranean.

  The Victorians were very fond of using ice to create puddings of all sorts. One example would be the Nesselrode Pudding, which consisted of chestnuts, vanilla, eggs and, of course, ice. This complicated pudding was beloved by Victorians for its refreshing taste and was a sign of wealth and class. A full recipe can be found at the Historic food website. The pudding is named after Count Nesselrode who was a patron of the culinary arts and had many dishes named after him. Ice puddings and snow cones were in turn the precursors to ice cream, the origin of which there is much confusion over.

Recreation

Ice has long been used for recreational purposes. Here is an example of the more intensive side of using ice for amusement as well as an example of using ice to show humanity's refinement. There is also a third example to show that both can be combined together.

• Ice Hockey

  Considered by much of the world to be the most violent team sport in existence, ice hockey is by no means a weak man's² sport. With six players per side, all of them carrying clubs³, it carries a serious risk of injury. The whole game must be played on ice, while wearing ice skates and moving at up to 20mph.

• Ice Sculpting

  One medium used by sculptors is ice. Unlike clay it has a high chance of shattering while being worked upon, but can be crafted by either hard implements or by application of heat, which gives a greater ability for sculptors to add texture to their work. By far the most common form of ice sculptures is the ice swan, seen in ice palaces or wherever someone wants to add a touch of assumed elegance.

• Ice Skating

  When ice skating is mentioned many will immediately think of Torvill and Dean. This famous pair won a gold medal at the Sarajevo Olympics with an outstanding combination of flair and artistic perfection. That ice skating can be dramatic is often questioned until skaters achieve flips while gliding through the air. Less often questioned is the way that ice skating adds to the world's culture. Ice skating bears many similarities to ballet and indeed other dance forms as well. Those of an artistic nature have called it poetry in motion.

Accommodation

Ice has several advantages and disadvantages as a building material. Here is the basic functional igloo, the sublime architectural masterpiece of the Jukkasjarvi Icehotel and as a last resort, a snow shelter.

• The Igloo

  Used for millenia by the Inuit and other extreme Northern people the igloo provides a warm space that also keeps out the freezing winds. They are normally built in a half sphere as it has the strongest shape and allows the wind to flow around it. The ice is simply cut into slightly curving blocks and built in a spiral until the top is reached. At that stage the person inside⁴ must cut the entrance/exit.

• The Icehotel

  In Sweden there is the Jukkasjarvi Icehotel constructed entirely (surprise, surprise) from ice. Around 4,000m³, it is constructed from 30,000m³ of river ice. Hundreds of builders form the strangest temporary structure in the world that now boasts its own bar and ice church. This advanced ice hotel is not to be confused with ice-houses, which were first used in 2000 BC in Mesopotamia, sometimes known as the cradle of civilisation. These sprung up in warm climates to house ice underground, and continued to be used to store ice even in the UK until modern technology made them obsolete.

• Snow Shelters

  If the worst happens and you are caught outside and you haven't taken the obvious precautions of packing a tent or carrying flares, or if you're very unlucky and have been caught in some kind of natural disaster⁵ then you will need to dig a snow shelter – see Digging a Snow Shelter for instructions.

Medical Uses

Ice also has its medical uses, particularly in the treatment of bumped heads and painful swellings. As ice can stick to skin if given the chance, it is important to cover any ice applied to the skin with a plastic bag or tea towel first.

How Ice Allows Humanity to Exist

Ice and its other forms of water and steam have some attributes that are incredibly strange. H₂O behaves like no other compound or element on the planet. Its closest chemical equivalents have boiling temperatures of -70°C. This would mean that all water on Earth should have long ago boiled away, leaving Earth as a very salty desert.

This strange property is due to weak bonds that form between hydrogens on different individual molecules of water. This is known as hydrogen bonding, the net effect being that water requires a lot more energy before these bonds are broken and the molecules can fly off individually as steam. The power of the bonds thus means water's boiling point is nearly 200°C higher than it would otherwise be. Hydrogen bonds are in fact the strongest intermolecular force to be found in nature; other compounds, such as hydroxides, also undergo hydrogen bonding with other strange effects.

By far the strangest property of water is how it behaves when frozen. Unlike most other substances, water doesn't become denser when it freezes – quite the opposite. While liquid water has a density⁶ of 1 g/cm³, ice has a density of around 0.9 g/cm³, allowing it to float. If ice sank to the bottoms of rivers and lakes as it froze, then the freezing would continue until all the river or lake was frozen solid, killing all life within it. Instead, the frozen ice forms an insulating layer on the surface and protects the life below it.

Ice's chemical properties are very strange, not just slightly different from water's, as you might expect. Examples of this are all around us but the most beautiful would have to be the humble snowflake. Despite the common belief that no two snowflakes are alike, it is possible for snowflakes to form identically.

Freezing Point

As humanity uses different temperature scales but drinks the same water here are a few of the scales and the temperatures where ice becomes water. Both the Celsius and Fahrenheit scales are defined using a set number for water's freezing point – zero for Celsius, 32 for Fahrenheit. It's worth noting that the two unusual scales, Kelvin and Rankine, use the same degrees as Celsius and Fahrenheit respectively, but start at absolute zero, which is a lot colder than water's freezing point.

• Celsius 0°C
  
• Kelvin 273.15K
• Fahrenheit 32°F
• Rankine 491.67R

These temperatures are for pure water with no impurities at normal atmospheric pressure⁷. The 'triple point' of water, at which ice, liquid water and steam exist in equilibrium with one another, is at 0.01°C.

One other important fact is that pure water can be cooled to as much as -42°C. This occurs when there are no nucleation sites – tiny impurities such as pieces of dust – for the ice to begin forming around. When the temperature drops low enough the water will freeze regardless and do so extremely quickly.

Curiously ice can in fact take a number of forms, each with a different crystal structure. Most of these form under high pressure however and so are rarely seen by anyone outside of a laboratory.

The Life-Threatening Dangers of Ice

Ice causes a great number of deaths each year, has done so for millennia, and will continue to do so for the foreseeable future. Here are the three biggest dangers and ways to minimise the risk, assuming that you plan to do any of these things at all.

• Avalanches, enormous slides of mountain snow, are unsurprisingly the biggest risk that ice poses. Avalanches are set off by either warming, extreme cooling, or people. Climbers can be crushed by hundreds of tonnes of snow and ice which can then set like granite, thereby hampering rescue efforts. For advice on avoiding avalanches, see Avoiding Avalanches - Basic Safety and Survival Tips.

• Crevasses are huge vertical cracks in the ice which are often covered by a very thin layer of ice. Though the thin crust of ice often covers a large plummet, it isn't just the fall that causes death but the greater problem of being stuck inside. This last problem is less problematic if you are part of a large group with ropes. Even on your own it could be fixed with an improvised grappling hook⁸ or a couple of ice axes. Better yet is to avoid the crevasse entirely; test all the ground in front of you with a ski pole, always testing it under a good amount of weight.

• One more problem is not actually caused by the ice's existence but by it being too thin. In many northern countries⁹ truckers make long voyages driving solely on ice floating on top of lakes in order to deliver cargo. Convoys of up to 50 trucks drive through the night over ice of varying thickness. Sometimes the ice is too thin and trucks plunge through the ice, and all too often the drivers cannot get out in time. If you cannot avoid driving over thin ice then the only real precautions you can take are to not wear a seatbelt and leave the door open in order to be able to bail out quickly. Another important requirement is to be friends with the other truckers so that they'll stop to help you.

• Icebergs are the most well known problem of ice. Though they still pose a threat to ships, the most famous incident with an iceberg was the sinking of the Titanic in which 1,500 perished. Icebergs are normally found just after the thawing of polar ice each year. They can drift a considerable distance before melting, posing a risk to ships below the Artic Circle.

Dangerous and Problematic Issues with Ice

As well as the numerous fatalities caused by ice there are other areas where ice causes considerable financial loss and a steady stream of injuries, a few of which are fatal.

• Icy roads are the bane of almost any country not on the equator. Enormous amounts of money are spent on machines and grit to keep the roads clear of ice. Despite this, transport is slowed to snail's pace and many cars end up off the road. Icy roads are primarily a problem where there is only the occasional snow fall, as it isn't worth the upkeep to maintain large numbers of gritters. Where ice is common, snow wheels can be fitted to cars to minimise problems; elsewhere, snow chains offer a cheaper solution that can be used where necessary. In the worst cases it can be helpful to carry some supplies such as food, water and a torch in your car in case you need to camp out.

  One particularly nasty form of road ice is the near-invisible black ice. The primary method to deal with black ice is to have a good winter driving ability. To minimise your risks simply drive slowly and don't brake too hard. Starting off in second gear and minimising revs will help avoid wheel spin, and allowing plenty of space between cars is vital to avoid accidents. Practice can be gained by taking lessons on skid pans, where drivers are taught how to deal with the most difficult conditions. Four wheel drive generally only helps in snow if the drivers are experienced in snow conditions.

• Ice build-up: a rather general term, it covers all the faults in machinery caused by ice buildup from operating in cold areas. Moving parts can jam, sensors can become inoperable, and computers rarely function at optimum levels in cold temperatures. The worst problem though is that of batteries. Batteries run for only a small fraction of their expected lifetimes when in very cold weather. Ice build-up only causes infrequent human problems (such as power cuts) but the financial strain is enormous. Little can be done about this except to try and insulate any machinery as far as possible and maintain redundant back-ups in any crucial systems.

• Engine icing is primarily a risk to jet engines. Water is sucked into the engines at which point it freezes. Ice pellets are capable of damaging the blades of the turbine, forcing them to shut down. If planes lose thrust due to engine shutdown then the pilots are required to learn how to glide their planes very quickly. Normally this isn't a risk as engines rarely shut down simultaneously. The primary risk of this can be found on descent as there is less time to recover thrust and take appropriate action.

• Erosion: ice dramatically increases the rate of erosion of cliffs where there is already impact weathering from waves. Water is less dense when it is solid, and thus any water that gets into a crack in rock, and then freezes, expands and may shatter the rock. Many countries around the world are struggling to save diminishing coastlines. People who have their property on coasts are obviously most affected, being faced with the slow march of the sea towards their homes. To stop this you will normally need the government to build sea defenses such as groynes and rip-rap. One possible way of helping yourself is to plant stabilising plants, which will slow the rate of erosion.

The Irritating Qualities of Ice

After listing all of the true dangers of ice you can now see some of the problems that you may well have encountered in life. Ice can just make life a little harder than it need be at times, whether we're trying to tame it for our use or just trying to carry on with our lives.

• There are are a few problems with ice cubes in drinks. They are frequently unwanted and will chill drinks to the point of being impossible to drink. The solution is reasonably simple – take the ice out – but normally most people will simply grit their teeth and bear it. Also, the ice cubes will melt, diluting the drink, following which the drink will begin to warm up. Adding more ice cubes will cool it down but further dilute the drink – the only advice here is to finish your drink as soon as possible. Finally, there is the issue of bars and fast food restaurants adding large amounts of ice in order to save money by providing less actual drink.

• Icy pavements are to blame for numerous cuts and bruises sustained by the world's populace, and are particularly dangerous for the elderly. Solving the problem is normally quite simple: either grit the pavement as you would a road, or take a different path.

• The stickiness of ice is particularly odd: while strange at first sight, anyone who has spent more than a day in icy conditions will have seen someone stuck to a lamppost or something else metallic by their tongue, or even tried it themselves. Ice will form between any mildly moist body surface and a frozen object, hence sticking it to the victim. This Researcher had the unpleasant experience of rowing in water that was only liquid because it was flowing:

  The oars stuck to our hands as we rowed and then when taking them back to the boathouse had to be sprayed with warm water as they froze to our hands, despite being made out of carbon fibre.

  To avoid this sort of problem, simply don't let skin touch frozen substances. Put a barrier such as clothing between you and the frozen object; if you do get stuck, pour warm water over your skin until free, and then dry it off.

As you've seen, ice is critical to both the survival and destruction of humanity, as well as our amusement. Humans have tried to subdue ice for millennia and have to a certain extent succeeded, and yet every day we are tricked by this close relation to the most common substance in our lives. It is also safe to say that final victory will go to the ice, especially if it comes in the form of the following.

Ice Ages

The first ice age is believed to have occurred around 2.5 billion years ago, followed by another around 700 million years ago. In both cases the world was completely covered in ice, making it nearly incapable of sustaining complicated life. The most recent ice age ended 14,000 years ago, though it was followed by another cold snap known as the Younger Dryas. We are currently in an interglacial period, where the world is much warmer, and yet we are still in the midst of an ice age. It is believed that this period should last for at least another thousand years; however human greenhouse emissions are affecting all of these predictions, making future conditions far harder to predict. While at first glance these greenhouse emissions should be extending our expected period of warmness, a rise in temperatures may actually lead to global dimming where the world cools. If another ice age were to come and humanity was not ready for it, the damage to our species would be catastrophic and, in the worst case, irrecoverable.

A Few Interesting Facts

Ice, like water makes a good substance for neutrino detection. To detect a neutrino you need millions of tonnes of a transparent substance. As the poles have lots of ice a project called IceCube has been built at a cost of 270 million dollars per year. It monitors a volume of one cubic kilometer of ice, looking for high energy pulses produced when a neutrino collides with a molecule of ice.

If the thin layer of ice present on Jupiter's moon Europa covers a liquid ocean, it could be protecting one of the few places in our solar system that could be capable of sustaining life. Due to this NASA has listed it high on places where they would like to send a rocket, and even more considerately decided not to dump the nuclear power plant from a Jupiter orbiter onto the ice.

Some planets are believed to have ice near their centres - but at incredibly high temperatures. This is possible because under very high pressures the particles cannot move around, even if they are very energetic. This could allow planets to have icy, rather than metallic, cores, although little evidence has so far been found for ice within Jupiter or Saturn.

Appreciating Ice

Earth currently resides in a state of equilibrium – for the first time since the Earth formed, we have ice caps at both poles while no snow falls on the equator. Glaciers contain the majority of all fresh water on Earth and feed many of the rivers that our ecology is based on. Were humanity to lose a considerable part of our glaciers, we would also lose a considerable part of our ecology and our fresh water supplies. Protecting the ice must be a crucial goal for humanity, primarily by the restriction of greenhouse emissions. Without ice there would be no more snow – no longer could children play in the UK's streets while the rest of the country is plunged into chaos by a mere 20cm of snowfall.