Understanding Un n Weather The Earth is surrounded by a layer off air called T ca the th atmosphere. Weather on Earth th is caused by b the heating of the air in the lower ower part pa of the atmosphere by the Sun. un. The heating heat and cooling of the air causes it to move mo in different ways. Thiss movement of air is called wind. Air also contains wa water in the form of a gas called water vapor. vapo The heating and cooling h g of air causes cause the water vapor to condense into va nto clouds. clouds This can cause ca c au it to rain or snow. snow
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Weather is always changing. The weather in the We eat ys changing morning may be morn mo e different from the weather in the afternoon. a noon. Weather changes from day to day and from season to season. Weather is also different in different places.
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Activity A ctiv 9.1
