Now do this put-the-text-back-together activity.
This is the text (if you need help).
The Sahara desert is twice as old as we thought. Science books say it is three million years old. A new study from a climate research centre says it is seven million years old. Researchers calculated when North Africa became desert. Their tests showed that global warming seven million years ago dried a lot of the land in Chad. A sea started drying so there was less rain. This helped to make sand dunes in Chad. This may be how the Sahara started.
The Sahara is one of the most famous and biggest deserts. It covers 10 per cent of Africa. It stretches from the Atlantic Ocean in the west to the Red Sea in the east. A geologist in Germany does not think the Sahara is so old. He wants to see more evidence. He said the new research is just based on numbers. He said nothing in the Sahara is older than 500,000 years old. Our knowledge of the Sahara climate starts from 10,000 years ago.
Back to the Sahara Desert lesson.
