How do ocean currents impact on climate?

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

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

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

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)

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 ……..

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

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

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

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

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?

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

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

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

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

What have you learnt?