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Published byPatrycja Sokołowska Modified over 5 years ago
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Starter: Look at the photos – what do they all have in common?
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… they were all created by … ICE!!!
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Learning Objectives To explain how ice (or a glacier) erodes the landscape. To describe the landforms ice creates in mountainous areas. To decide what activities are best suited to such landscapes.
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What is a Glacier? A glacier is a like a river – only it is made of ice and it flows much, much more slowly (about 7 – 10 km a year). A glacier is made when lots of snow gets squashed into ice and then it slides downhill. The ice in a glacier is so thick and heavy that a huge amount of pressure is exerted at the base and this melts the bottom couple of centimetres. This ‘meltwater’ reduces friction between the ice and the rock below so the ice flows downhill like a frozen river.
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Where are Glaciers found?
Today, glaciers can be found anywhere it is cold enough. Most big mountain ranges have glaciers, like the Alps, the Rockies, the Andes and the Himalayas.
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Did you know……? In the last Ice Age, lots of the UK was covered by ice, and that meant there were lots of glaciers!!! The ice didn’t melt until about 10,000 years ago and we can still see the effects of this ice in the landscape of the UK today – look at the photos on the next slide for evidence.
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Tasks Write down 3 facts about glaciers – make sure you comment upon the following: What a glacier is. Where glaciers are found today. Plus …. One other interesting fact!!!
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How does Glaciation Change the Landscape?
During glacial periods freeze-thaw weathering of the landscape occurs. Watch this clip and listen closely. Look at this diagram. Tasks Why do you think freeze-thaw weathering happens in glaciated areas? Can you describe what the fragments of rock which break off are like and what do we call them? What is this process sometimes called? Make a copy of the sketch below which shows freeze-thaw action. Add your own labels to explain how it happens and add a title.
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Glacial Erosion This is the wearing of the land by ice and there are 2 important ways in which the ice erodes the landscape. Abrasion - this is when the scree (from freeze-thaw action)embedded in the glacier act like apiece of sandpaper, scratching and scouring the rock at its base. It leaves behind deep grooves called striations. Plucking – this is when the rocks at the side or the bottom of the glacier become frozen to the ice. The rock is attached to the ground so cannot move, but the glacier continues to flow. This usually rips the rock away, leaving a jagged landscape. (think about putting an ice cube on your tongue – ouch!!!)
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Tasks 5. Look at the diagram below showing the ice flowing over the bedrock. Draw a sketch of this diagram. Add annotations to show which process of erosion is happening where and explain how it operates. Can you add arrows to show the direction you think the ice is flowing in?
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Plenary Do you know who this is?
This is George Herbert Leigh Mallory (18 June 1886 – 8 or 9 June 1924). He was an English mountaineer who took part in the first three British expeditions to Mount Everest in the early 1920s. During the 1924 expedition, Mallory and his climbing partner Andrew Irvine, both disappeared on the North-East ridge during their attempt to make the first ascent of the world's highest mountain. The pair were last seen when they were about 800 vertical feet (245m) from the summit. Mallory's ultimate fate was unknown for 75 years, until his body was discovered on 1 May 1999 by an expedition that had set out to search for the climbers' remains. Whether Mallory and Irvine reached the summit of Everest before they died remains a subject of speculation and continuing research BUT ….. Why was his body found 800 metres from where he is thought to have died? Watch this clip ….
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Learning Objectives To explain how ice (or a glacier) erodes the landscape. To describe the landforms ice creates in mountainous areas. To decide what activities are best suited to such landscapes.
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Glacial Landforms Starter:
Watch this clip and list on your wipe board as many different landforms created by ice as you see. We will only look at the 3 main landforms created in the upland areas: Cirque/Corrie Arête Pyramidal peak Now watch this clip very carefully.
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Glacial Landforms Look at the photo and diagram below. They show a typical upland glaciated area. Make a sketch of either the photo or the diagram and give it a title. Now read the descriptions on the next slide and annotate your diagram correctly. Don’t just copy out the information – choose key words carefully to describe and explain how each landform made.
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A corrie (or cirque) is a bowl-shaped hollow found on the side of a mountain. They form when ice collects in small hollows on the side of the mountain. As the ice starts to move downslope, abrasion works to deepen the hollow whilst plucking makes the backwall steeper. Often, when the ice has long since melted, corries are filled with small, circular lakes, which are called tarns. When 2 corries form back-to-back they produce a steep, knife- edged ridge called an arête, and when 3 or more corries form on top of a mountain they create a pyramidal peak
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What activities are best suited to these adventure landscapes and why?
In pairs, try and come up with 3 different activities that you could do in upland glaciated areas? What do these landscapes offer in terms of adventure?
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Plenary 3 key words that I have learnt and understood over the past 2 lessons are… If I was to research something in more detail, I would be interested in learning about ….
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