Key words : circular rotate axis propeller turbine mobility journey (v) vehicle invention civilisation

A. Look at the pictures and say which one is easier to move and why.

B. Read the text and answer the following questions.

Human beings have invented many important things so far. They have brought great civilization to the world through these inventions. Do you know which invention is the greatest? It is 'the wheel'.

A wheel is a circular object. It can rotate around its axis and help easy movement of things across a surface.

The wheels are, in fact, everywhere. They are on our cars, trains, planes, wagons and so on. Besides, they are on most factory and farm equipment. Fans, propellers, turbines are also other types of wheels.

So the wheel is very important. We cannot imagine modern life without wheels. But do we know exactly who made the first wheel?

Questions

1. What is a wheel?
2. What can a wheel do?
3. Where can you find wheels?

C. Fill in the blanks with appropriate words from the box. There are more words than necessary.

Although the wheel is a very (a) ------ invention, the history of its origin is unknown. Experts guess that the first wheel was developed from a circular object. The early man observed that a huge piece of stone could be rolled easily if it was (b) ------ in shape. Similarly, a heavy tree-trunk is (c) ------ to carry; but it can be rolled away with less effort. Even, a gigantic tree-trunk can be moved easily using other small and round trunks as rollers under it. Thus, early man took advantage of rolling objects and developed the (d) ------ wheel. Apart from its mechanical advantage, a wheel's mobility has contributed (e) ------ to the civilisation.

D. Make as many correct sentences as you can using the substitution table. In the third column there are more items than necessary.

E. Have you ever travelled by bus or car? Do you have any experience of what happens if one wheel falls flat. If yes, give a description of your experience. If no, imagine such a situation, and write a paragraph on it.