Transcript Key point: What is a desert? A desert is a dry, often sandy region with little rainfall, extreme temperatures and very little plant life.

Key point:
What is a desert?
A desert is a dry, often sandy region
with little rainfall, extreme
temperatures and very little plant life.
The Sahara is very hot!
Look at the location of Sahara on the map!
Why is it so hot? What is it near to?
The temperature on a Winter day is
about 30 degrees. On a Summer day
it can be over 50 degrees celcius!
The world's highest recorded temperature was in the Sahara
Desert.
In one day it can go from 0 degrees at night to
40 degrees in the day!
Deserts get cold at night because there is no
water and there are no plants to hold the heat
on the ground and because dry air cools
quickly.
It rarely rains in the Sahara.
In some areas there is as little as 5mm of rain in a
WHOLE YEAR.
Some areas go years without ANY RAIN at all !!!!!
When it does rain it tends to be a
BIG THUNDERSTORM after a long dry spell!
Winds
Weather brings some strong winds to the Sahara
Desert.
These winds can blow for days and bring a lot of
dust and sand with them.
They can cause SANDSTORMS and DUST
STORMS/DUST DEVILS.
During sandstorms, the wind lifts up
grains of sand and bounces them around.
Very unpleasant – and painful for
the people in The Sahara.
Howling winds whip up sand which cuts
their faces and hands and gets into their
eyes, noses, and mouths.
The people of The Sahara have special names
for the Sand Storms!
Sand grains are heavy, so
storm is low to the ground.
A wild sand storm is called Haboob and the wind that
sweeps sand across the desert from March until May is
called Khamsin, which is Arabic for ’50 days’.
Dust devils can also pick up sand,
leaves, paper, and sometimes
other objects.
Spin at 25 miles an
hour but they last for
Only a few minutes.
They have small width, but they can
rise as high as half a mile.
A dust devil may look like a miniature tornado.
The planet Mars has dust storms, too.
The dust is made up of soil, dried leaves, volcanic ash,
parts of meteorites that have burnt up in the atmosphere,
plant pollen, mould, fungus, bacteria and germs. So it is
NOT HEALTHY TO BREATHE IN THIS DUST!
Two million people (2000000) still live in The Sahara.
But 60 million live in the UK and it is much much smaller!
People must wear protective clothing in The Sahara.
People live where there is water – not in the centre of
The Sahara.
Not many people cross the Sahara.
Not many people come on holiday here – only to places where
there are rivers or on the coast. One example is Egypt!
NOT MANY PLANTS AND ANIMALS CONSIDERING ITS SO BIG!
THESE PLANTS AND ANIMALS HAVE ADAPTED TO THE CLIMATE.
BUT STILL….SOME PARTS OF THE SAHARA HAVE NO PLANTS OR ANIMALS.
The African Peyote Cactus can hold
water for a very long time, until it
rains again.
The African Welwitchsia.
Long spread out roots (корни) under the ground.
This helps the plant survive by helping it reach
(достигаемость)out to get more water out of the
ground because it rarely rains in the desert.
Plants must be able to absorb water and retain it.
The African Camel has…
Two sets of eye lashes on each eye and
bushy eye brows to protect their eyes from
the sand.
Can go up to a week without drinking and still survive.
Can drinks lots and store it.
Has wide padded feet so they can walk over the sand.
Stores fat in humps.
The African Monitor is cold blooded.
This helps the animal keep his or her bodies cooler
so they do not overheat in the hot desert sun.
Addaxes
Large, flat hooves for walking over the sand without sinking.
Can go without water for a long time.
Dig holes in the ground for shade.
Some animals come out at night when it is cooler!
Some animals look for shade in the day.
Are there any patterns that you
can see on this map?