1. How do ocean currents impact on climate?

2. Pressure systems and weather
By the end of the lesson you will;
Be able to describe and explain the weather associated with a high and low pressure system
Be able to explain global distributions of high and low pressure systems
Be able to explain how high and low pressure systems can impact on the UK
Have applied your new knowledge to an exam style question

3. Air pressure
Our atmosphere is made up of tiny molecules of nitrogen, oxygen, carbon dioxide and other rarer gases
These molecules have mass and actually press down on us – this is what we call air pressure

4. High and low pressure Task
You need to recreate the picture at the front of the classroom
You need to add in as much detail as possible
Winning groups get sweets

5. Describe pressure systems
Low air pressure
Warm air
Molecules further apart
Warm air rises
Molecules even further apart
LOW PRESSURE
970 – 990 Millibars (mb)
High air pressure
Cool air
Molecules closer together
Cool air falls
Molecules even closer together
HIGH PRESSURE
1020 – 1040 Millibars (mb)

6. Pressure systems Task Explain what a high and low pressure system is
Use as many of the key words as possible
Explain the different types of weather associated
Key words
Hot
Cold
Rising
Sinking
Clouds
Condensation
Rain
Sun
Clear
Drought
Flooding
Winds
High pressure systems have sinking air. They are associated with cold temperature in the winter, and hot temperature in the summer. They will have clear skies and can lead to drought.
Low pressure systems will have rising air. Air rises and condenses to form clouds. This will then lead to large amounts of rain. If over a long period of time, there will be flooding. There can also be wind that is associated with a low pressure system
A high pressure system will have……….
A low pressure system will have ……..

7. Pressure systems and weather
By the end of the lesson you will;
Be able to describe and explain the weather associated with a high and low pressure system
Be able to explain global distributions of high and low pressure systems
Be able to explain how high and low pressure systems can impact on the UK
Have applied your new knowledge to an exam style question

8. What type of pressure system do you think each city has in the forecast?
Cape Town, South Africa; Sunny, 25 degrees, Clear Skies London;, England, Cloudy with rain, 3 degrees, low visibility Vilankulos, Mozambique; Sunny; 42 degrees, Cumulus clouds Siberia, Russia; Clear Skies, -23 degrees Kibera, Kenya 37 degrees, cumulo-Nimbus Clouds, heavy rain showers.
Using your white boards, decide if each city is experiencing high or low pressure

9. How are pressure systems formed and distributed?
Atmosphere is cooled in the polar regions. Cold air sinks forming an area of high pressure
Between 35N and 65N mixture of high and low pressure belts moving from west to east. Makes weather very changeable
Task;
Study the information
What weather will be associated at 0, 30, 60 and 90 degrees?
How does the weather affect the features found at 30 degrees?
What weather system are we in the UK affected by?
Around 30 degrees the air sinks back down causing a high pressure system
Around the equator, the air is rising causing a low pressure system

10. Pressure systems and weather
By the end of the lesson you will;
Be able to describe and explain the weather associated with a high and low pressure system
Be able to explain global distributions of high and low pressure systems
Be able to explain how high and low pressure systems can impact on the UK
Have applied your new knowledge to an exam style question

11. Impacts of High and low pressure;
Task
Each of you has an article on one pressure system
You need to make notes
Be ready to teach the rest of the class
Social Impacts
Economic Impacts
Environmental impacts
Low pressure system
High pressure system
Extension;
How might the impacts of low pressure systems be reduced in the future?

12. So what are high pressure systems and how do they impact the UK?
High pressure systems are called Anticyclones
Bring high pressure and settled conditions lasting for days or weeks
Clear skies – VERY FEW CLOUDS
In summer they are associated with clear warm weather
In winter they bring clear, bright, cold days. As heat is lost at night, the mornings are cold and frosty.
Isobars in a high pressure system increase in value towards the centre
Key Word; Isobars are lines on a map which indicate areas of similar pressure

13. Depressions
Depressions bring areas of low pressure which usually bring rain and cloud and wind to the British Isles.
They usually develop to the west of the British Isles over the Atlantic ocean
Warm moist air from the South meeting colder drier polar air from the North.
2 air masses because they are different densities cannot mix and so the warm less dense air is forced to rise over the cold denser air.
NICE and easy;
“when the weather is not very nice we get really depressed.”
Clip of a depression

14. Pressure systems and weather
By the end of the lesson you will;
Be able to describe and explain the weather associated with a high and low pressure system
Be able to explain global distributions of high and low pressure systems
Be able to explain how high and low pressure systems can impact on the UK
Have applied your new knowledge to an exam style question

15. Applying your new knowledge
Task
With reference to a named example
describe the causes of a low pressure system
Explain the impacts of this low pressure system
Level 1;
Student does not name an area
Student gives general ideas that are not linked to a specific case study
Level 2;
Student names an area
Student describes the causes of low pressure
Some impacts are added in but lacking in detail
Level 3;
Student describes the cause of low pressure
Geographical terminology added in
Student uses a minimum of 3 figures in their answer
Impacts are divided into Social / economic/ environmental

16. What have you learnt?