25 Incredible Inventions：Computers

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Incredible Inventions Computers by Thom Anthony Table of Contents Introduction page 2 Chapter 1 Life Before Computers page 4 Chapter 2 The First Computers page 6 Chapter 3 Modern Computers page 8 Chapter 4 Today and Tomorrow page 12 Conclusion page 14 Glossary/ Index page 15 Comprehension Check page 16

Introduction Take a look around you. Do you see any computers? Computers can be found at home or school. They help make clocks and traffic lights work. They are inside watches and cars, and many other objects. A computer makes this audio player work. Computers can be found in some clocks. The shape of this computer keyboard was designed for easy use. Computers can be used in an office for work. But they can also be used at home for fun. You can play games and songs on a computer. You can make art and music on one too. Learning about what a computer can do can be as much fun as using one. So, get ready to read about how computers have changed our lives.

Chapter 1 Life Before Computers One of the first things people made to help them keep track of numbers was called an abacus. It is made of rods and beads. By sliding the beads on the rods, people can do arithmetic. The Chinese abacus was first made about 5000 years ago. It is still used in some parts of China and Japan. This is an abacus. Amazing Inventions: The Calculator A calculator is a small machine that does math. You can use it to add, subtract, and much more. In 1650, two men in England created the first slide rule. A slide rule is made up of two rulers with numbers written on them. The rulers can be slid back and forth to solve math problems. The slide rule was used for a very long time. When calculators and computers came into use, most people stopped using the slide rule. Slide rules come in a number of different styles.

Chapter 2 The First Computers One of the first computers was called the ENIAC. It was completed in 1946 and it was very big. ENIAC weighed as much as seven elephants and took up as much room as a house. Six people were needed to keep it working. It could perform about 500 addition and 300 multiplication problems per second. The letters ENIAC stand for Electronic Numerical Integrator and Computer. Early computers had a lot of problems. They could only do one thing at a time. It cost a lot of money to build one. Early computers also took up a lot of space and created a lot of heat. They could break down easily. This early computer cost $20,000. Soon, smaller computers that could fit inside a home or an office were built. But they were still slow and expensive. So most people did not buy them. But people wanted to have them and soon they would be able to.

Chapter 3 Modern Computers In the 1970s, a new, small device called the microchip increased the speed of computers. Now people could buy desktop computers that worked faster and cost less. Computers became more common in offices, schools, and homes. Many libraries have desktop computers for people to use. A microchip In 1981, Adam Osborne built a small computer that was also very light. It was called a laptop. Laptops can do the same things that desktop computers can do. But people can use them in a smaller space. Laptops can weigh as little as three pounds. Since they are light, people can carry them from work, to home, to school. They can operate on batteries too. This means that people can use them when they travel. People often bring a laptop computer on board a train so they can work while they're traveling.