One fun fact about deserts is that not all deserts are hot, but all deserts are dry. Another fun fact is that the largest desert in the world is a region of Antarctica where less than 2 inches of precipitation falls annually. This is called a polar desert.
The Sahara Desert in Africa is the largest hot desert in the world. The Sahara is home to a 200 million-year-old volcano called Emi Koussi. The driest desert in the world in the Atacama Desert in South America. Less than 1/2 inch of rain falls each year in the Atakama.
Even in hot deserts, night time temperatures often fall below freezing. The sun heats the ground during the day, which also heats the air. In other places, clouds have the potential to help trap the heat to make day and night time temperatures less extreme, but clouds rarely occur in deserts. Without clouds, all the heat escapes into space leaving the desert nights very cold.
The word desert means "abandoned place," but the desert is teeming with life. Even though little water exists, deserts are home to many species of plants and animals. Plants such as cactus and some shrubs adapted themselves to require very little water. Coyotes, hares and many reptiles also call the desert home.