Measuring the Depth of Greenland’s Ice Sheet

The thickness of the Greenland ice sheet was first measured by German Scientists in 1930. They set off explosives in holes drilled a few meters down into the ice. The forces of the explosion compressed the ice nearby. The compression set up shock waves that traveled in all directions. Waves traveling through the surface layers of the ice were detected by microphones spread out on the ice. Other waves went down through the ice. The solid rock beneath the ice reflected the waves to the surface, where the microphones detected them.

Mathematics tells us that rate multiplied by time equals distance. The scientists knew the distance waves had traveled at the surface and the time taken, so they could easily figure out the rate, or speed, at which the waves traveled through ice. Knowing rate and time, they could then work out the distance the waves had traveled between the surface of the ice and the rock below. This gave them the thickness of the ice.

The Germans found the ice near the edge of the ice sheet was about 1, 500 meters thick. It was even thicker in the middle of South Greenland. Sine World War  II, scientists of many countries have made measurements. In parts of Greenland the ice is more than 3, 000 meters thick. In many areas the bottom of the ice is below sea level.

A fast, easy way of measuring ice thickness has been used recently. A plane flies over the ice sending out bursts, or “pulses”, of radio waves. The waves pass through the ice and are reflected by the underlying rock. Instruments in the plane measure the time it takes the waves to return to the plane.

Aside from the thick ice sheet, Greenland is also great for its mega canyon which was hidden for a long time already under the ice sheet.

The Antarctic Ice Sheet

Antarctica is one-half times as large as the United States. All of this continent, except some small areas, is covered with ice. In western Antarctica, the ice sheet rises to about 2, 300 meters above sea level. The deepest part of the ice sheet is nearly twice as its thickness. The rock beneath this great mass of ice is 2, 400 meters below sea level in one area. If the ice were to disappear, the coastal part of western Antarctica bill become a series of lands. In eastern Antarctica, the shape of the land at the bottom of the ice is less well known. The surface of the ice rises about 4, 000 meters above sea level. In the areas where explorations have been made, the bottom of the ice is found to be about 600 meters below sea level. After years of measuring, scientists can estimate the total volume of ice in Antarctica. If it all melted, sea levels the world over would rise about 45 meters.

Ice Shelves

Large ice shelves fringe the coasts of Antarctica. The largest are the Ross and Filchner ice shelves. Both are big as the state of Texas in the United States. The ice of the shelves floats on the sea, but it is not formed by the freezing of the sea water. Shelf ice forms from the glaciers that spread seaward from the inland parts of the continent. The ice of the Ross shelf, 300 meters thick, moves northward at speeds of more than one kilometer a year.

Ice islands

Sometimes the front of an ice shelf breaks off into the ocean, forming huge flat-topped icebergs, One such iceberg, discovered in 1927, had an area more than 25 000 square kilometers. This great iceland must have been more than 180 meters thick. Antarctic icebergs are formed from the usual shipping lanes and melt long before they can drift into them.

Ice Ages

Ice ages are times when thick sheets of ice have spread over large parts f the continents. The ice sheets form when glaciers of high mountains and polar regions grow to great size. Slowly, over hundreds and hundreds of years, the glaciers reach out. They cover the land with sheets of ice that may be several thousand feet thick.

During the earth’s history their have been several ice ages, The last one often called the Ice Age, began at least 3 million years ago. At least four times during the Ice Age greet sheets of ice advanced over the land. Each time they melted and drew back.

The last advance ended about 18 000 years ago. At that time a large part of North America was covered by ice. The ice reached as far south as the site of New York city now. Areas of Northern Europe and Asia were also partly covered with ice. Both these large regions are still covered with ice sheets as thick as 2.5 kilometers. This fact raises an important question: has the Ice Age really ended, or will glaciers advance again?

Clearly, people need to answer that question. During each spread of ice, world conditions change greatly. Air and ocean temperature were far lower than the present. Places that are now the sites of great cities were completely ice-covered. Other areas, now deserts, were well watered and covered with plant life. And with great quantities of water trapped n glaciers on the land, sea levels were vastly lowered. Those were just few of the great changes that affected the Earth during the advances of ice. Advances are called glacial stages. Each glacial stage was followed by an intergalactic stage. This was a warmer time, after the ice melted and before the next glacial stage.

Watch this documentary about Ice Age.

Ice Hockey

Ice Hockey is also known as the national sport of the country of Canada. It first appeared during the 19th century. It was assumed that the first planned game took place during the year of 1855, when English soldiers in Kingston, Ontario, played on the frozen surface of the Lake Ontario. The sport quickly spread to other army garrisons and also to the near by towns. Around 1875, students at a university in Montreal was able to develop a code of rules or also known as the McGill Rules. Using these rules, teams from different cities began to play against one another, and leagues soon sprang up. In 1893, Canada’s governor-general, Lord Stanley of Preston, donated a cup to be given o the country’s amateur champions. By 1896, teams were playing in the New York area. Canadian and American teams competed against each other for the first time in 1899.

Amateur hockey has been long significant part of the Northern American sport scene. Increasing emphasis began to be placed on the fitness and amateur sports in the 1950s to 1960s. Efforts were made to provide children with the opportunity to learn and play ice hockey in supervised leagues rather than just one local pond.

The Canadian Amateur Hockey Association or CAHA was formed in 1914 to promote and regulate amateur hockey. Since then, it has operated country-wide junior and senior leagues. Today, it also organizes leagues throughout for children 5 years old and above. About 600, 000 players and 33, 000 teams are currently registered with CAHA. The Amateur Hockey Association of the United States of America or also known with its abbreviation of AHAUS was formed in the year of 1937. Originally, it had four leagues with fourteen teams. Today, the organization direct scores of leagues with thousands of players. in 1930, hockey became an official sport at the Olympic Winter Games where the Canadian team won the first gold medal.

Watch some jaw-dropping hockey plays in the video below!

Learn How To Ice Skate

Ice Skating is very elegant to look at, if you do not keep falling on the ice floor. However, you can not learn skating if you do not fall for a few times. Here are easy steps on how to learn, even for the first time on skates.

First thing to learn is always to get your balance. Keep your head up, do not look down and do not bend forward. Both of your arms should be at your waist and keep your hands relaxed. Keep both of your feet together, slide them back and forth a little bit, and try to glide along on these two feet. Your first steps on the ice may be frightening, but do not worry, each step will be an improvement. It will not be long until you will get used to the feeling of being in skates.

After you already improved your gliding, you can begin practicing stroking. Bend slightly forward at the waist. Push off from the front part of the blade on either foot. Never push of using your toe picks. If you are pushing off with your right foot, bend your right knee as you begin to stroke and straighten it as you end your glide. Do the same for the left foot.

You must also learn how to stop. Glide in a straight line with your feet about more than one ruler apart. Then, force your heels apart and point your toes together to make a snowplow position. This will bring you to a halt. More experienced skaters use hockey stop.

You must learn how to turn. The best way is using a crossover method. Your free foot should pass in front of your skating foot. Then your free foot is placed on the ice and your weight shifted for it. For example, if you wish to turn to the right while skating on the right foot, bring the left foot  in front of the right. Shift your weight gradually until the left foot  crosses over the right and touches the ice on the inside edge. The left foot now carries the weight and the right food can be lifted from the ice. Bring it up beside the left foot up and cross it in front as before. Repeat these steps.

The three kinds of Speed Skating

Olympic-Style Speed Skating

It is usually used for international competition. The pane is 400 meters to the lap. The tracks are divided with snow lanes about two thirds of the way around. The part not divided is called the crossover. Only two skaters race at one time and they can change lines by using the crossover at every lap. Each skater is individually timed. The world championship and any sectional or national championship are decided by an allover point total.

Pack Skating

In pack skating, a group races together to series of rounds. There are 5 racing divisions in pack skating. They are Senior Class, Intermediate class, Juvenile Class and Midget Class. Outdoor tracks are shaped oval. On the other hand, the indoor track differs when it comes to sizes. Classes have different sizes of tracks. The winner of each race is determined by a series of preliminary races which are also called heats. Usually the first and second place finishers of each heat race against each other until the winner is determined. Points are also given in pack skating. Unlike Olympic-style skating, the fastest skater in each race gets the most points. After all the races are done, the skater with the most points is the champion.

Short-Track Speed Skating

The track for short-track speed skating is shorter than an Olympic speed-skating oval and has no marked lanes. There are three kinds of speed-skating competitions that use the short track. They are individual races, relay races and pursuit races. The individual races are divided into five short events and one long event.. A series of heats determines the winner for each distance. Heats in the short group have no more than four skaters. Six skaters may race in the long race. Relay races consists of two teams of four skaters. Each team member skates until replaced by a teammate. A skater ma be replaced t any time except during the final two laps of the race.

Watch this fascinating video to see what it’s all about!

Glaciers

Glaciers

Glaciers are found at present in the regions around the North and South poles and in mountainous areas elsewhere. Near the equator in South America and Kenya in Africa, some of the mountains are about 4, 500 meters which is about 15, 000 feet. It is high enough for the average air temperature to be well below freezing point. Thus, there are glaciers in equatorial lands as well as in polar ones. Of course, for glaciers to form at all, snow must fall A few places in Antarctica have no glaciers simply because very little snow falls.

Ablation

As the ice in the glacier flows downhill to warmer altitudes the amount of melting increases. Some of the melt water may soak into the glacier and refreeze. The rest either flows of the glacier in streams or evaporates into the air. These processes, by which ice is lost from the glacier, are called ablation. Some glaciers reach the sea and melt when they come in contact with the warmer seawater. Calving, the name used when larger icebergs break off a glacier and float away, is also a form of ablation.

Accumulation

Let’s take a glance at a glacier in a mountainous area High up in the mountains, the amount of new snow and ice added each year is greater than the amount lost by melting and evaporation. This upper part of the glacier is called the accumulation area. Farther down the mountain, ablation is greater than accumulation of snow. This part of the glacier is the ablation area. At some level on the glacier, summer melting just balances the winter;s accumulation of snow. This level is called the firn line. Above the firn line, the glaciers surface is permanently snow-covered. Below it the surface is ice in the summer and snow in the winter.

Watch this fascinating video of a glacier wave below!

Ice In Nature

Ice From Water

One example is a small pond and then it freezes during a cold winter. During the summer, the water becomes warmer. It absorbs heat from the sun, an it is in contact with the warm air. As winter approaches, the air temperature drops The water ten loses heat to the air, and its temperature falls.

To understand what happens next, you have to know another fact about water. It is heaviest at 4 degrees Celsius. At temperatures higher or lower than this, it is lighter. As the surface of the pond cools to 4 degrees C, the water on the top becomes heavier and sinks to bottom. When it sinks, it pushes warmer and lighter water up from below. The new surface water cools, sinks and pushes more bottom water to the surface. This circulation continues until all the pond reaches at temperature at 4 degrees C. When all the water reaches at that temperature, the surface of the water will continue cooling until it is lighter, As a Result, the pond starts to freeze at the surface, while the bottom remains with the 4 degrees Celsius temperature. Because water is heavier than ice, plant and animal life can survive in the water, ponds and lakes would freeze from the bottom.

Ice From Snow

The other way that ice forms in nature is from snow. In most places where winter snows exists, temperatures later climb high enough to melt all of the snow that has fallen. In every high mountain areas and in the polar regions this is not the case. In those regions, some of the winter snow stays formed as solid. This makes it bigger through out time. In areas where there is some melting, a density of snow increases much faster. This is so because some of the water from melting trickles down through the rest of the snow and fills the air spaces between snow crystals. Later it refreezes and make ice.

Watch this amazing video of a lake slowly freezing over time.