Deserts are areas that receive less than 100mm of rainfall per year. Hot deserts are found between 30 degrees north and south of the equator, where there is little cloud cover and the sun's rays directly heat the land. Deserts are dry because of high pressure systems that form at 30 degrees latitude, which prevent cloud formation and rainfall. The lack of clouds also means heat easily escapes at night, leading to large temperature fluctuations.

1. WHy are deserts hot and dry?

6. Sonoron Great Victorian Gobi

10. Latitude and Longitude Lines around the Earth, like the Equator Lines down the Earth, like the Greenwich meridian

11. What are the major lines called? 23.5 degrees S Latitude Tropic of Capricorn 23.5 degrees N Latitude Tropic of Cancer Where one day jumps to next 180 DEGREES E/W Longitude International date line Divides into East and west 0 degrees E/W Longitude Greenwich Meridian Divides Earth into north and south O degrees N/S Latitude Equator significance degrees Lat/long Line

12. Equator Tropic of Cancer Tropic of Capricorn Arctic Circle Antarctic Circle 0 º 23 ½º 66 ½º 23 ½º 66 ½º North South 0 º Greenwich Meridian East West International Date Line 180 º Sun overhead 21 June Sun overhead 21 December Time goes ahead Time goes behind Sun does not rise on 21 Dec Sun does not rise on 21 June

14. Deserts are found here And here

15. Rainforests Deserts

16. Sun hits at right angles and heat has less distance to reach land so is stronger Sun has further to travel to land, because of the curve of the Earth so it’s weaker and less hot Why? Therefore it gets hotter the closer you are to the equator

17. At 30 degrees north and south of the equator there are NO CLOUDS and so the full force of the sun’s rays can hit the earth….making it very hot!

18. What happens at night? At night time the clouds at the equator act like a giant blanket. They trap some of the heat that is leaving the earth and keep it nice and warm In the desert there is no blanket of clouds and so all of the heat from the earth simply escapes into the atmosphere. So it can get very cold in the desert at night. There have even been reports of frost found in the desert!! At 30 degrees north and south of the equator there are NO CLOUDS and so the full force of the sun’s rays can hit the earth….making it very hot! In the daytime…..?

22. Why are deserts dry? It’s all about pressure! Air presses down on land , which brings fine weather as clouds do not form High pressure Low pressure Air rises from the land as it rises it cools, condenses into clouds and causes rain Rain

23. Hottest part of planet At 0 degrees it is hot and wet At 30 n and s it is hot and dry

24. Low pressure at equator High pressure high At 30 degrees north and south of equator the air sinks forming high pressure which brings dry fine weather At equator warm air is forced to rise as it does, it cools, condenses and forms clouds and you get rain

25. The air around the Earth is always on the move, both across the surface and up and down in the atmosphere.

26. No clouds so at night heat escapes to space Clouds keep heat in at night Deserts Rainforests Sun high in sky so hot Sun high in sky so hot No clouds (clear sky)= no rain Clouds form= rain High pressure Low pressure 30 DEGREES NORTH AND SOUTH Equator (0 DEGREES)

28. Question 3a answers Air presses down on land , which brings fine weather as clouds do not form High pressure Low pressure Air rises from the land as it rises it cools, condenses into clouds and causes rain Rain

30. Why are deserts found on the west of continents? North East trade winds South East trade winds South East trade winds North East trade winds equator

32. Why is the Atacama the driest desert in the world? Atlantic ocean Winds to South America blow from the Atlantic ocean to the Pacific ocean Pacific ocean So it rains along the Atlantic coast and inland Once it gets to the Andes mountains it is lacking moisture At the Andes air has to rise Andes Mountains

33. As it rises It cools, creating LOW pressure = clouds = rain. Mountains cause a rain shadow effect- behind them it does not rain By the time the air reaches the top of the mountains it has lost all of its moisture. As the air sinks down the other side of the mountains it warms up. = HIGH pressure = no clouds and no rain. But some animals & still plants survive there Atlantic ocean Pacific ocean