5 Forming desertsDeserts are formed by weathering processes as large variations in temperature between day and night put strains on the rocks which consequently break in pieces. Although rain seldom occurs in deserts, there are occasional downpours that can result in flash floods.
6 PlantsPlants living in the desert need special adaptations to survive in the harsh environment. Plants tend to be tough and wiry with small or no leaves. Some annual plants germinate, bloom and die in the course of a few weeks after rainfall while other long-lived plants survive for years and have deep root systems able to tap underground moisture.
7 AnimalsAnimals living in the desert need special adaptations to survive in the harsh environment. Animals need to keep cool and find enough food and water to survive. Many are nocturnal and stay in the shade or underground during the heat of the day.
8 Little precipitationA desert is a region of land that is very dry because it receives low amounts of precipitation, often has little coverage by plants, and in which streams dry up unless they are supplied by water from outside the area. Deserts can also be described as areas where more water is lost by evapotranspiration than falls as precipitation. Deserts generally receive less than 250 mm (10 in) of precipitation each year.
9 Dust storms and sandstorms Sand and dust storms are natural events that occur in arid regions where the land is not protected by a covering of vegetation. As wind begins to blow the particles get lifted up into the air. Particles can be in the air for days.
10 TemperatureDesert surfaces receive a little more than twice the solar radiation received by humid regions and lose almost twice as much heat at night. Many mean annual temperatures range from 20-25°C. The extreme maximum ranges from °C. Minimum temperatures sometimes drop to -18° C.
11 SoilSoils often have abundant nutrients because they need only water to become very productive and have little or no organic matter. Disturbances are common in the form of occasional fires or cold weather, and sudden, infrequent, but intense rains that cause flooding.
12 DesertsDeserts cover more than one fifth of the Earth's land, and they are found on every continent.
13 DesertsDeserts are second only to tropical rain forests in the variety of plants and animals that live there.
14 Sahara desert The largest hot desert on Earth is the Sahara. The Sahara Desert is located in northern Africa, spanning 12 different countries.