Presentation on theme: "7Ie The water cycle Click on part of the picture to find out more."— Presentation transcript:
7Ie The water cycle Click on part of the picture to find out more.
7Ie The water cycle Evaporation Heat from the Sun warms water in seas, lakes and rivers and the water evaporates. Water also evaporates from wet ground and from plants. Heat from the Sun also warms the air, and the warmed air rises. The rising air takes the water vapour with it.
7Ie The water cycle Condensation Rising air carries water vapour with it. As the air rises it cools, and the water vapour condenses to form clouds. Clouds are formed from millions of tiny drops of liquid water.
7Ie The water cycle Rain Drops of water in the clouds join up. Eventually the drops are too big to stay in the air and they fall as rain.
7Ie The water cycle Hail and snow If the air is very cold, the water droplets in the cloud may freeze to form snow or hail. A hailstone is a small ball of ice.
7Ie The water cycle Rivers and lakes Rain falling on land can soak into the ground or run across the surface. Some of this water evaporates again, but most of it runs into streams and rivers. Some rivers flow into lakes. In some places dams are built to make reservoirs. The water from reservoirs is used to supply drinking water to homes.
7Ie The water cycle Treating water We all need water for drinking, washing and cooking. Water is taken from the ground or from rivers and lakes. It is cleaned and treated before we use it, to make sure it is safe to drink.
7Ie The water cycle Waste water Waste water from homes, factories and businesses is treated to make it safe before it is put back into rivers or into the sea.
7Ie The water cycle Back to the sea Water in rivers runs back into the sea.