Why Do Droughts Happen?A drought is a shortage of precipitation over a period of time. A drought begins with a disruption to the water cycle, the circulation of water from the Earth's atmosphere to its surface. The water cycle doesn't always operate so smoothly. When it doesn't, an area can have a drought or a flood.
Changes in air pressure can affect the water cycle. Air pressure is the force with which the air presses against everything. This force is caused by gravity. Air rises when there is low air pressure at ground level. This rising air carries water vapor, which can create clouds and precipitation. Air sinks when there is high pressure at ground level. The high pressure prevents the air from rising to create clouds and precipitation. If a high-pressure system stays in an area for a long time, it can cause a drought.

Most droughts are temporary, and can occur in all climates. Some climates are permanently dry, or arid, such as desserts. Droughts get worse when rivers and streams dry up, so they cause people without water to drink and to grow food.

Question :
5. How does a drought start?
A. The sun lights stronger.
B. There is no clean water.
C. There is global warming.
D. A flood hits some countries.
E. The water cycle doesn't operate smoothly.

6. What can affect the water cycle which causes
droughts?
A. Changes in air pressure.
B. The gravity.
C. The high pressure of ground level.
D. The high-pressure systems.
E. All climates.

7. We know from the text that droughts are said worse when....
A. there is no drinking water
B. they happen in desserts
C. plants cannot grow
D. rivers and streams dry up
E. water cycle is disrupted
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