We usually don’t think about ice too much, unless there’s none in the freezer and all we have to drink is a warm can of Coke. Artificial refrigeration has been around for almost a century now, and it’s safe to say that we take ice for granted, just as we will take food for granted when the replicators come online.
But the cold, hard, slippery truth is that ice deserves more consideration than that- and not just the kind you put in your drink. There’s much to be learned about our past, present and future from studying the cold stuff, so grab yourself a nice beverage or a refreshing popsicle and prepare for a brain freeze.
10. Ice Harvesting
Before the advent of freon-based refrigeration in the early 1900s, ice was the only way to keep things cool (and food from spoiling). While there were ice-making machines in use in the mid- to late-1800’s, they were mostly for commercial use – beef packing plants and the like – and also used dangerous chemicals such as ammonia and ether.
But ice was still needed for the home, and commercial ice harvesting was a huge business around the turn of the century. The process was every bit as labor-intensive as one would imagine it to be without the use of modern tools- gigantic ice picks and saws, along with horses pulling around what amounted to huge ice plows, were common for larger jobs, which could employ dozens of men for months at a time. Ice was then conveyed mechanically or by river to an ice house.
Thousands of small, private ice houses- along with dozens of much larger, commercial ones- dotted the American landscape at this time. Ice houses were double-walled, tightly insulated structures packed with sawdust and other insulating materials, capable of keeping large amounts of ice through the warm months. One of the larger ice houses, on the shore of Connecticut’s Bantam Lake, was the length of two football fields, contained fourteen compartments, and could store 112 million pounds of ice. Much of this ice departed daily by train, for the larger cities including New York- up to twenty cars full per day.
Of course, it still had to make its way to the home, which is why before refrigerators, there were…
9. Ice Delivery and Iceboxes
As one might imagine, New England dominated the early ice industry. It had plenty of the stuff to harvest each year, and sawdust from its many timber mills was readily available for insulation. Frederick Tudor, father of the New England ice trade, was shipping ice all over the world by the middle of the 19th century; cleverly, he mitigated the shipping costs by shipping fruit and other perishables along with the valuable ice.
By the turn of the century, the icebox was just as common in American homes, grocers and restaurants as electric refrigerators are today. As you can see from the illustration, the principle was largely the same: ice was kept in a top compartment; as the air cooled, it was forced down to where the food was stored; warmer air rose, where it would be cooled by the ice, and so on. Melt was caught in a drip pan underneath the unit, and every morning, the friendly neighborhood Ice Man would come by with another fresh chunk for you. Depending on the region, ice could be gotten for as little as four cents per pound.
Old-fashioned ice boxes were often beautifully hand-made; since they were not necessarily thought of yet as kitchen appliances, their look was more in line with living room decor.
If you punch the surface of a lake, and then a block of ice, you’re probably insane. You also might be tempted to think that ice is far denser than water. While there is no disputing that ice is HARDER than water, this would display a misunderstanding of the scientific property of density.
One curious property of ice is that as it freezes, it expands (this is why standing water in your pipes will cause them to burst if they freeze). Put another way, as water freezes, it retains the same mass while taking up more space- about 9% more. This means that ice is actually quite a bit less dense- its molecules are spaced farther apart- than water, which reaches its maximum density at about 40 degrees Fahrenheit (slightly above freezing).
This is why ice floats in water– which, actually, is a pretty important mechanism for life on Earth. It’s also what causes potholes in the road in cold areas, and why a can of soda will burst when frozen.
7. Different Types
While most probably figure there is more than one type of ice, there are actually sixteen that are known to science. Their different properties present themselves at different atmospheric pressures and temperatures; Ice IV is the kind you find in the freezer.
Among the types that science has helpfully labeled I through XV (9), the major differences lie in the structures of the crystals; some strange properties emerge under certain conditions. For example, Ice XI is ferroelectric- it exhibits electric polarization, which can be manipulated and reversed. Ice V has the most complicated crystalline structure; Ice III is actually denser than water, and would sink if you put some in your glass.
Strangest of all is the one type not classified by number, which is called amorphous ice. It has no crystalline structure, and is the type of ice most often found in space; there are also three different types (depending on density) of this amorphous ice, which is closest to simply being a solid form of water- it’s actually classified as a mineral.
6. Slippery When Cold
So, why is ice slippery? Sure, it’s made out of water, but what about ice that’s at far below freezing temperature? It stands to reason that if it’s ten below freezing outside, the ice should be frozen hard enough to be a solid surface, with no liquid water on it, and that it should not be slippery enough for us to fall and damn near break our tailbone on the way to work. This, obviously, is not the case.
Before the phenomenon was properly understood, science took an educated guess that sounded right, so it was widely taught in textbooks; basically, that friction (caused by your foot) caused an ever-so-slight raising in temperature at the surface of the ice, which produced a microfilm of water, which made you slip before immediately freezing up again. It sounds plausible, but unfortunately, it was a bit off the mark.
The real reason has to do, again, with ice being less dense than liquid water. Scientists within the last decade have come to believe (no, this is still not completely understood) that because of this difference in density, and through a principle that would take six (very boring) lists to explain, surface molecules of ice- those in contact with air- cannot bond properly to the mass of molecules beneath. These surface molecules essentially retain liquid properties while being solid ice, and even we couldn’t make up an explanation that cool for ice being slippery.
5. Commercial Production
When one thinks about a world without refrigerators, it’s easy to imagine how gigantic an industry commercial ice production must have been a hundred years ago. What’s really mind-boggling is just how enormous an industry it remains to this day- only now, of course, it’s produced mechanically instead of harvested from natural sources.
Commercial ice makers today produce three main types- flake (shaved ice), tubular (the little pellets you still see in some ice machines), and plate (regular cubes). In addition to being bagged and sold commercially, it has many industrial uses including the manufacturing of chemicals, and is used in mixing concrete.
Believe it or not, there’s enough demand for ready-made ice that, as recently as 2002, a census study showed over 400 ice production companies generating almost $600 million annually in the United States. That’s JUST from producing and selling ice, and doesn’t even count companies that manufacture smaller ice makers for food service and such.
4. Building Material
When we think of structures made of ice, it’s safe to say that not a lot jumps to mind beyond the igloo. But ice has shown to have many practical uses in building- and some NOT so practical, if totally dazzling.
For example, Antarctica’s McMurdo Sound is a remarkably inhospitable place. Fuel tankers and supply vessels had a hell of a time even docking there until 1973, when the U.S. Navy devised an ingenious solution to the difficulty of building a pier in the ice- they built a pier FROM the ice. The process has since been perfected, and five more such piers built, each lasting several seasons before being allowed to melt.
Attempts have even been made- not quite so successful- to build structures or vessels out of what is called pykrete, which is a mixture of 86 percent ice with 14 percent wood pulp. The pulp reinforces the naturally brittle ice, resulting in an extremely resilient- if obviously temporary- substance. The British military considered the viability of building warships out of the substance during World War II (it was not viable).
And finally, there is the more recent phenomenon of ice hotels like the one shown above, which pop up annually during the cold season at various locales inside the Arctic Circle. Such hotels typically use ice not only for the architecture but the furniture, light fixtures, even drinking glasses and art objects. Polar-rated sleeping bags are the only real amenity, which is great, since they’ll be necessary for surviving your stay.
Glaciers don’t exactly ignite the public imagination, even if one played a co-starring role in a very successful movie about a famous, doomed ocean liner. But consider the facts that water is obviously important to human life, that glaciers are made of water, and that ten percent of the Earth is covered with them.
In fact, fully three quarters of the fresh water in the entire world is contained in glaciers. Think about that; the volume of every fresh water lake in the world is nothing compared to the volume that sits frozen around the Earth’s poles, and if all of the glaciers in the world suddenly melted, we’d all be a couple of hundred feet underwater as a result. Also, seasonal glacial runoff is an incredibly important source of fresh water- for example, in Washington state alone, 470 billion gallons of water are produced each year from glacial melt.
One glacier range in the Canadian Arctic has been found to produce ten percent of the glacial melt in the entire world. The range is the size of the state of New York, and is pretty much a primary reason for rising sea levels worldwide.
2. Ice Core Drilling
The Greenland Ice Sheet covers 80% of that land mass- the world’s second-largest body of pure ice, after the one in Antarctica. At the bottom of it, miles below the surface, there is ice that froze over a hundred thousand years ago. In 1955, scientists began drilling there, collecting core samples of the ice; over the decades, many tools and techniques have been developed for extracting very well-preserved ice samples from far, far below the surface.
Contained therein is a record of climate change all throughout history. Using air samples trapped inside the ice, scientists are able to gather information about the temperatures and greenhouse gas levels of hundreds of centuries past. They hoped to determine how hot surface temperatures were during the last interglacial warm period before our current one, and how the planet coped- and thereby, perhaps gain insight as to how we could do the same if temperatures continue to rise.
And they may have been successful. The most recent research suggests that temperatures were up to eight degrees hotter during this period- the Eemian period- than the present day, and sea levels 13 to 26 feet higher … in other words, “a number of environmental climatic conditions that could possibly be reproduced in the future.”
1. Indicator of Extra-Terrestrial Life
Finally, as alluded to earlier, ice is everywhere in space. Hydrogen and oxygen are among the most plentiful elements in the Universe – in fact, scientists believe that most, if not all, of the water on Earth came from ice-bearing comets and asteroids that smashed into the planet in its infancy.
Being a requirement for life as we know it, liquid water would be great for astronomers to find on some distant planet- but ice would be almost as good. Life has been found on our own planet, in the form of microscopic organisms and tiny shrimp, beneath the previously mentioned ice shelves of the Antarctic, an environment long thought uninhabitable by life of any kind; why not on the brutally cold surface of another planet?
Or, perhaps even a moon- Jupiter and Saturn both have moons chock full of ice, with other conditions science thinks may have at least once been favorable to life. All food for thought the next time you’re pouring your sun tea over ice, the stuff that may hold the key to the search for intelligent life in the Universe.