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© Boardworks Ltd 2005 1 of 30 These icons indicate that teachers notes or useful web addresses are available in the Notes Page. This icon indicates the.

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Presentation on theme: "© Boardworks Ltd 2005 1 of 30 These icons indicate that teachers notes or useful web addresses are available in the Notes Page. This icon indicates the."— Presentation transcript:

1 © Boardworks Ltd 2005 1 of 30 These icons indicate that teachers notes or useful web addresses are available in the Notes Page. This icon indicates the slide contains activities created in Flash. These activities are not editable. For more detailed instructions, see the Getting Started presentation. 1 of 30 © Boardworks Ltd 2005 Weather in the UK

2 © Boardworks Ltd 2005 2 of 30 The British Climate The British Isles has a temperate climate. This means that it is not too hot, not too cold, not too dry and not too wet!

3 © Boardworks Ltd 2005 3 of 30 Learning objectives Why is the South of Britain warmer than the North? Why are temperatures in January warmer on the West coast? Why is there more rainfall in the West? What is high and low pressure? Why is the weather in the UK so changeable?

4 © Boardworks Ltd 2005 4 of 30 July temperatures Isotherms are lines joining areas of equal temperature. Iso means the same.

5 © Boardworks Ltd 2005 5 of 30 1)What is the temperature at A? 16ºC, 15ºC, between 15ºC and 16ºC 3) Which area is the hottest? Look at your atlas and name this area. 2) What is the temperature at B? 4) Which of the following statements is true? a) The North is warmer than the South. b) The East is warmer than the West. c) The South is warmer than the North. A B July temperatures

6 © Boardworks Ltd 2005 6 of 30 Why is the South of Britain warmer than the North? Therefore, the suns rays are more concentrated in the South rather than the North of Britain.

7 © Boardworks Ltd 2005 7 of 30 Learning objectives Why is the South of Britain warmer than the North? Why are temperatures in January warmer on the West coast? Why is there more rainfall in the West? What is high and low pressure? Why is the weather in the UK so changeable?

8 © Boardworks Ltd 2005 8 of 30 between 4ºC and 5ºC Match the letter with the correct temperature. January temperatures A B C 4ºC4ºC between 5ºC and 6ºC Why is B colder than C, even though B is further south?

9 © Boardworks Ltd 2005 9 of 30 Why is it warmer in the West in January? The North Atlantic Drift is a warm ocean current that brings higher temperatures to the west of the UK. The North Atlantic Drift starts its journey in the Gulf of Mexico.

10 © Boardworks Ltd 2005 10 of 30 Learning objectives Why is the South of Britain warmer than the North? Why are temperatures in January warmer on the West coast? Why is there more rainfall in the West? What is high and low pressure? Why is the weather in the UK so changeable?

11 © Boardworks Ltd 2005 11 of 30 Describe the pattern of rainfall in the UK. Why is there more rainfall in the West of the British Isles? Rainfall in the British Isles

12 © Boardworks Ltd 2005 12 of 30 Why is there more rainfall in the West? Many of the mountain ranges in the British Isles occur in the West. The West is therefore more likely to experience relief rainfall.

13 © Boardworks Ltd 2005 13 of 30 Why is there more rainfall in the West? The prevailing wind comes from the SW. This wind blows over the Atlantic, bringing moisture-laden air. The prevailing wind is the most common direction of wind.

14 © Boardworks Ltd 2005 14 of 30 This is a wet day in February. Explain the following… 1) why C is warmer than B.2) why it is raining at D. 3) why A is colder than B. Can you explain?

15 © Boardworks Ltd 2005 15 of 30 Learning objectives Why is the South of Britain warmer than the North? Why are temperatures in January warmer on the West coast? Why is there more rainfall in the West? What is high and low pressure? Why is the weather in the UK so changeable?

16 © Boardworks Ltd 2005 16 of 30 Getting practical

17 © Boardworks Ltd 2005 17 of 30 When air rises, it creates a low pressure system. Air rising means clouds form and there is a possibility of rain. Low pressure systems

18 © Boardworks Ltd 2005 18 of 30 When air sinks and warms this causes a high pressure system. There are clear skies and no rain. In Summer, clear skies mean that there are no clouds to stop the sun shining through and so days can be warm. High pressure systems Cloud free Europe At night, however, there are no clouds to stop the heat escaping so nights can be cool.

19 © Boardworks Ltd 2005 19 of 30 In Winter, high pressure systems give rise to clear, bright days. However, clear skies also mean that there are no clouds to stop the heat escaping and so ice and frost can form. High pressure systems

20 © Boardworks Ltd 2005 20 of 30 Learning objectives Why is the South of Britain warmer than the North? Why are temperatures in January warmer on the West coast? Why is there more rainfall in the West? What is high and low pressure? Why is the weather in the UK so changeable?

21 © Boardworks Ltd 2005 21 of 30 Why does the British Isles have unpredictable weather? In the British Isles it can be sunny one minute and raining the next! Why is this?

22 © Boardworks Ltd 2005 22 of 30 Why does the British Isles have unpredictable weather? The answer has a lot to do with air masses… Air masses are huge blocks of air. They can be damp or dry, warm or cold, depending on where they came from and over what type of surface they have travelled. For example, an air mass that has travelled over the sea will increase its moisture content and be more likely to produce rainy weather.

23 © Boardworks Ltd 2005 23 of 30 Air masses affecting the British Isles Many air masses cross the British Isles, which explains our changeable weather!

24 © Boardworks Ltd 2005 24 of 30 What happens to the weather when the air masses meet? Depressions (low pressure system) form when a cold air mass meets a warm air mass. The junction between these two different air masses is called a front. A front is associated with a change in the weather.

25 © Boardworks Ltd 2005 25 of 30 What happens at fronts? A cold front means that cold air is coming. At a cold front, cold air pushes under the warm air. This produces strong winds and heavy rain. A warm front means that warm air is coming. At a warm front, warm air is rising over cold air. This usually produces clouds and rain.

26 © Boardworks Ltd 2005 26 of 30 Passage of a depression

27 © Boardworks Ltd 2005 27 of 30 Formation of a depression Click on the red labels find out more!

28 © Boardworks Ltd 2005 28 of 30 Depressions

29 © Boardworks Ltd 2005 29 of 30 Depressions – the changing weather!

30 © Boardworks Ltd 2005 30 of 30 Weather definitions


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