Class seven short test no.2 Flashcards
Define the Term desert !
A Desert is an area which usually has no or only little vegetation because it is too dry. There are two reasons for the aridity: -1: there`s not enough precipitation because the air is too dry or too cold.
-2: evaporation is very high because of night temperatures.
There are two main types of deserts:
hot deserts ( tropical deserts) and polar deserts.
Name at least 5 facts about the desert !
Possibilities:
- deserts cover a fifth of the Earths surface.
- 13 percent of the worlds population live in deserts.
temperatures of 58 degrees Celsius were recorded in Azizia in Libya.
-no rain as fallen for over 40 years in some places of the Atacama desert in Chile.
- night temperatures in some deserts can fall below freezing.
- sand dunes can be up to 300m high
- sand covers less that 20 percent of the worlds desert areas.
- dust from the Sahara has sometimes been carried to Germany.
- the Sahara Desert covers 8 per cent of the world`s land area.
- there are 1,200 different kinds of plants in the Sahara.
Name all the Continents and Countries where you can find these deserts!
a: Mojave desert
b: Atacama Desert
c: Sahara Desert
d: Namib desert
e: Arabian desert:
f: Thar desert:
g: Kara Kum and Kyzyl Kum Desert
h: Takla Makan and Gobi desert
i: Great Victoria Desert
j: Simpson Desert
Letter/Continent/Countries a/North America/USA, Mexico b/South America/ Chile, Peru c/Africa/Mauritania,Chad,Sudan,Niger d/Africa/ Angola,Namibia e/Asia/ Saudi-Arabia, Oman, Yemen, Jordan f/Asia/Pakistan g/Asia/ Kazakhstan, Uzbekistan, Turkmenistan h/Asia/Mongolia, China i/Australia/Australia j/Australia/Australia
Give facts about the Arabian camel or dromedary !
There are two kinds of camel. The Arabian camel or dromedary is found in the middle east, India and North Africa. It has a single hump. It has larger than the Bactrian camel and has longer legs.
The other type of camel is the bactrian. It has two humps. The Bactrian lives in the deserts of Central Asia where the winters are cold. It is smaller than the dromedary and has a longer winter coat and short legs.
Why is the camel well adapted to the desert ?
- can close its nostrils in case of a sandstorm
- It`s feet have heavy pads to protect them from stones and hot sand.
- Can drink up to 200 liters of water and stores it in its stomach.
- eyebrows protect the camel`s eyes from dirt and dust.
- The camels red blood cells can become 200 times its size to store water so that it has water when it needs it.
- The camels fur traps a layer of air that keeps it cool during the day and warm at night.
- The camels hump doesn`t contain water, it contains fat so that the camel can go for a long time without food.
Name all the types of deserts and name a few examples !
-Coastal deserts: Nami Deserts Atacama Deserts Peruvian Coastal Deserts Poja Desert - Polar Deserts Antarctica -Mantare Desert e.g Himalaya Karakum Desert -rain shadow desert Mojave desert
How does a rain shadow desert form ?
Air masses are forced to rise along the southern edge of the mountain range. While the air is rising, it cools off
and clouds form. It rains. Dry air masses blow into the rain shadow behind the mountain.
How does a continental desert form?
Continental deserts can be found in the inner regions of continents. Humid air masses rarely reach these regions. Very cold winters and hot summers are characteristics.
How does a Coastal desert form ?
Coastal deserts are found where cold ocean currents reach the continent. Cold water from the depth of the ocean surges up along the coast. The rising water cools the air above the sea. Cold air is heavier than warm air. When the cool ocean air meets the warm air of the mainland, the cold air masses settle atop. A stable air layering occurs a “inversion”. The air no longer rises and clouds don`t form. Wherever the air above the ocean surface cools, fog banks are formed.
Explain the desert climate!
When the air over the equator rises is heated it rises. When the air rises it cools down. Then the water vapor condenses and there is heavy rain the tropical ( zenithal rainfall). The air over the equator moves on and and sinks to the ground . Over the deserts this now dry air sinks to the ground. There are no clouds that`s why it is hot during the day and cold during the night. Dry winds, the so called trade winds blow across the deserts towards the equator.
. Because of the hot and dry air we find big deserts in this area.
Define the Term Oasis !
A Oasis is a green island between the deserts. They are located where enough
water is available to feed plants. There are four different kinds of oases: the river oasis, the foggaras, the oasis with an arterian well Andean the groundwater oasis.
How does the Artesian Well work ?
The people trap the layer of water between two impermeable layers, so that the water cant rise or seep away. This builds up pressure, so that the water cant rise or seep away. This builds up pressure, so when the people drill into the hole water comes up the well.
How does a river oasis work?
Allackthonous rivers => Water is directed from a river directly to the gardens and fields through ditches or by the use of water lifts ( pr motor pumps)
How does a Foggara work?
This is a traditional form of watering an Oasis. They are kilometers long underground tunnels that bring water from the base of the mountain. They are hardly used today.
How does a Groundwater oasis work ?
There are near mountains where there`s regular rainfall. The rain sinks into the ground faster than it evaporates, and becomes groundwater, which people get through motorized pumps of buckets. You can also find these near a wadi.
