TEXT BOOK: IT

UNIT 1:

In the nineteenth century, machines changed the world.
Suddenly, people could travel more easily and contact one
another more quickly. Work changed, too, and many people
got jobs in factories. It was the start of the Industrial Age

 the age of machines and factories.

The second half of the twentieth century saw the start of
the Computer Age. At first, computers were very difficult
to use, and only a few people understood them. But soon,
computers began to appear in offices and then homes. Today,
they are everywhere. Some people still say that they have
never used a computer, but they probably use computers
every day - they just do not realize it. This is because there
are computers in so many things: cars, televisions, radios,
washing machines...

When the first computers were built in the 1940s and
1950s, they were as big as a room. In 1949, the magazine
Popular Mechanics made a prediction: 'One day,' they said,
'computers will be really small; in fact, they will weigh less
than 1.5 tonnes.' Now, computer chips can be smaller than
the full stop at the end of this sentence. Over the past fifty or
sixty years, computers have changed much more than people
thought possible.

UNIT 2:

For thousands of years, humans have needed to count.
Families needed to know how many animals, how much
food, and how much land they had. This information was
important when people wanted to buy and sell things, and
also when people died or gor married. There were many
different ways to count and write down the numbers. The
Sumerians had three different ways: they used one for land,
one for fruit and vegetables, and one for animals. They could
count, but they had no easy way to do calculations.

Around 1900 to 1800 BC, the Babylonians invented a new
way to count using place values. This meant that two things
decided the size of a number: the digits (the numbers from 0
to 9), and the place where they were put. Today, we still use
place values to count. We can write any number using only
ten digits: for example, 134 means 1 x 100,3 x 10, and 4 x 1.
Computers also use place values when they do calculations.
They only use two digits (O and 1): for example, 11011  means
1 x 16, 1 x 8, O x 4, 1 x 2, and 1 x 1 (=27). Without place
values, fast calculations are impossible.

Between 1000 and 500 BC, the Babylonians invented the
abacus. It used small stones which they put in Lines. Each line
of stones showed a different place value. To do calculations
they moved stones from one line to another. Later, different
kinds of abacuses were made. Some of them were made
of wood and used coloured balls. It is also possible that
the abacus was first invented in China, but nobody really
knows.

Although an abacus can be very fast, it is not really a
machine because it does not do calculations automatically.
In the seventeenth century, people began to build calculating
machines. In 1642, the French mathematician Blaise Pascal
made an Arithmetic Machine. He used it to count money.
During the next ten years, Pascal made fifty more machines.

In the 1670s, a German called Leibnitz continued Pascal's
work and made a better machine. Leibnitz's machine was
called the Step Reckoner. It could do much more difficult
calculations than Pascal 's Arithmetic Machine. Interestingly,
Leibnitz's machine only used two digits (O and 1) for its
calculations- just like modern computers! In fact, calculating
machines like Leibnitz's Step Reckoner were used for the next
three hundred years, until cheap computers began to appear.

ACTIVITIES

1. COMPLETE

 a) The industrial age started in the second half of the twentieth century
 b) Many people use the computers everyday
 c) The first computers were built in 1979 by Ada
 d) The abacus was invented in China, but nobody really knows
 e) A french mathematician made an Arithmetic Machine