The Water Cycle Flashcards
How does water play an important part in our lives
Our bodies are made up of 70% water. approximately 80% of the earth’s surface is covered in water.
It is continually moving from the Earth’s surface to the clouds and then back to the Earth again as rain and snow.
this affects our climate. this in turn affects the habitats on which many plants and animals depend.
What processes add water to the atmosphere
By far the greatest contributor of water vapour to the Earth’s atmosphere is evaporation from the Seas, lakes and land.
The second factor that contributes to water vapour to the atmosphere is plants and trees. Living plants naturally release water vapour from their leaves in a process called transpiration. This process cools down plants.
Another source is industry. Many industrial processes make steam as a by-product. This adds to atmospheric water vapour.
Burning fuels is another factor that adds water vapour to the air. When you burn gas, petrol or home heating oil water vapour is produced as a by-product.
What happens to the water vapour as it enters the atmosphere
As water vapour rises, it cools and turns from gas to liquid, a process known as condensation. The vapour is converted to cloud which consists of very small drops of water.
Some of these may be blown by wind over land. As it moves over land it may be blown higher over mountains and cool further.
What happened to the cloud and the water droplets in it?
At the cloud is forced to ride over hills and mountains, it may cool further. The cloud is no longer able to hold onto the water droplets and the water falls as rain, hail, Sleet or snow. This is known as Precipitation.
What happens to the water when it reaches the land
Most of the water makes its way back to the sea eventually. Water collects in streams, lakes and Rivers. This is known as run off. As it does so, it may collect minerals from the rocks as it passes over them.
Some water can soak deep into the Earth and it’s stored deep in the ground. This process is called infiltration.
In mountainous regions, water may be stored there for several months as snow. I spring, the snow may melt, releasing large amount of water into rivers and streams.
In polar regions no can stay frozen for thousands of years it can compress into layers below and form glaciers.
Steps and diagram of the water cycle
- Heat from the Sun causes water to evaporate from the oceans
- As water vapour rises it cools. Condensation produces clouds of tiny droplets of water
- Clouds rise and further cooling occurs. Drops of water become heavier and fall as rain.
- Water collects in streams and Rivers.
- Rivers flow to the sea. they dissolve substances from the rocks and received sewage and industrial waste.
- Some water is diverted to reservoirs
- This water is purified in the water treatment works.
- It is then used in homes and Industry.
- After use it is treated in sewage works
- It is then return to the rivers and the sea
What happens to water on its way back to the sea
Hydroelectric dams can trap the water and convert it’s potential energy into electrical energy in a generator.
Some is also routed to our homes and Industry for consumption.Water must be treated before it is consumed it is treated by filtration and adding chlorine to kill bacteria and viruses.
Water that has been used by houses and factories also needs to be treated. If it were released into rivers and the sea it would lead to an excessive growth of algae. this process is called eutrophication. it removes oxygen from water.
What are the benefits of the water cycle
Without the water cycle the land would be a desert. It will be necessary to irrigate the land to grow crops. It would make the cost of food much more expensive.
Without the water cycle there would be a lack of fresh clean water.
If the water cycle did not exist, we would have to desalinate (remove salt from) water for drinking, irrigation and washing
