司拿Geo 5.1 & 5.2 & 5.3 ocred page 3(1).pdf

In this unit you'll learn what drives the weather. It's the Sun! The weather. Windy ? Wet ? Warm ? The Sun is behind it all ... !/ water vapour rising rays from the warm air rises, and is the Sun pushed away (it's invisible) . . 7N B as cold air takes its place The Sun heats Earth. But i...

In this unit you'll learn what drives the weather. It's the Sun! The weather. Windy ? Wet ? Warm ? The Sun is behind it all ... !/ water vapour rising rays from the warm air rises, and is the Sun pushed away (it's invisible) . . 7N B as cold air takes its place The Sun heats Earth. But it does not heat it evenly, because Earth is round. The top and bottom don't warm up much. Earth in turn heats the air. The warm air rises. Air from a colder place then The Sun also warms the oceans. flows in to replace it, as wind. This causes water to evaporate to give a gas, water vapour. That gas plays (Wind is just air on the move,) a big part in the weather. Now look what happens when air The tiny droplets may join to form bigger drops. When these grow heavy enough, they fall from the sky as rain. water vapour everywhere The water vapour mixes through the air, helped by wind. So there is some in the air around you, even if you are miles from water. Honeal B s rises. It cools, which causes the water vapour to condense again, into clouds of tiny water droplets. It might rain all day. e Here toda { gone tomorrow. -t. Over here, 5 . Your eyes, they sparkle like the morning dew. | think. 7’ F s 5 Where are you? Y ey SN If the air is very cold, the water droplets may fall instead as snow, or sleet, or hailstones. It depends on the air temperature. 70 S Water vapour may also condense lower down in the air. For example in chilly weather, it may condense all around us as fog. Or it may hang in the air as mist. Or condense on grass and leaves overnight, as dew. Mist and dew evaporate again in the sunshine.