It all adds up Computer life Computers are one of the most common gadgets we use in everyday life Most households in the developed world now own one and they are found in most schools and libraries We use them to store our music and photographs research homework shop play games and keep in touch with friends This versatile tool came about through our need to count things Count on it People have been counting for many thousands of years However doing so exactly and making calculations has always presented problems as people often lose track of what they are doing and make mistakes For this reason they have looked for ways to help them get calculations right The earliest known counting device is the beaded frame called the abacus which was invented about 3,000 years ago It is still used today in many parts of the world An abacus is not a calculator The operator The abacus is still used in many countries today Here a Korean storekeeper uses an abacus to find out the total price of the goods he is selling Each stage of a calculation is recorded by moving beads across the frame
John Napier Date of birth 1550 exact date not known Place of birth Edinburgh Scotland Profession Mathematician Greatest achievement The discovery of logarithms Interesting fact There is a story that Napier wanted to catch a servant who had been stealing He put a rooster in a dark shed and said that the bird would identify the guilty person Each man had to go and stroke the bird Napier guessing that the thief would be afraid to touch it had covered the bird with soot The thief would be the only one to emerge with clean hands Date of death April 4 1617 still has to do the math in his or her head but moving the beads to different positions on the frame helps keep track of each stage of a calculation Logarithms For thousands of years using an abacus was the best way to do calculations Then in 1614 John Napier a Scottish mathematician discovered logarithms Logarithms make it possible to turn multiplication into addition To multiply two numbers you look up the logarithm for each in list of numbers called a table and add them together Adding is easier than multiplying Logarithms had a huge impact on science The astronomer Johannes Kepler for example had written about how he was driven to distraction by the calculations he had to do Logarithms made his work and that of other scientists much simpler They remained in use for more than three centuries until mechanical calculators and eventually computers replaced them 7
wanted to make a machine for him that would automate the process In 1623 he built a device that he called a calculating clock This was the first mechanical calculator Unfortunately before he could give it to Kepler it was destroyed in a fire The Pascaline The first mechanical calculator to be produced and actually used was the arithmetic machine or Pascaline designed by French mathematician Blaise Pascal in 1645 Numbers were entered into the machine by turning a series of dials Pascal designed the machine to help his father a tax collector Pascal built 50 arithmetic machines and managed to sell about a dozen of them In 1671 German mathematician Gottfried Wilhelm von Leibniz designed a machine called the step reckoner This was an improvement on Pascal’s idea because by adding numbers repeatedly it could multiply Calculators Living computers During the 16th to 18th centuries more and more of the world was being explored by Europeans The resulting trade boom was known as the Commercial Revolution The increase in travel and trade meant that faster ways of making calculations were needed The word computer was first used around the same time as Napier was discovering logarithms These computers weren’t machines they were people who made calculations or computations These could include calculating the positions of stars and planets for use in ships navigation charts Humans doing calculations all day may get bored tired and make mistakes So inventors looked for ways of making the task of computing faster and more reliable The search for a practical mechanical computer was on The calculating clock In 1617 the year Napier died German churchman Wilhelm Schickard met the astronomer Johannes Kepler and the two men became friends Kepler was using Napier’s logarithms as he studied the stars and planets but Schickard Although the original calculating clock was destroyed Schickard left a detailed enough description of it for this replica to be built It is in the Deutsches Museum in Munich Germany 8
Blaise Pascal Date of birth June 19 1623 Place of birth Clermont France Profession Mathematician and philosopher Greatest achievement Pascal is best known for developing a mathematical theory called the theory of probability Interesting fact Pascal set out an argument for believing in God called Pascal’s wager He said that if God does not exist one will lose nothing by believing in him But if God does exist one will lose everything by not believing Date of death August 19 1662 The binary system As well as making his step reckoner Leibniz was also interested in the binary number system and how it could be used In everyday life we use the decimal system of counting The decimal or base 10 system uses the numbers 1 to 9 and 0 Numbers are ordered in multiples of ten units in one column tens in the next hundreds in the next and so on The binary system uses just two symbols 0 and 1 So 1 is written as 1 but 2 is written as 10 meaning one 2 and no 1s Three is 11 one 2 and one 1 0 0 1 1 2 10 3 11 4 100 5 101 6 110 7 111 8 1000 9 1001 10 1010 Four is two 2s which is 100 just as 10 tens are 100 in the decimal system Five is 101 two 2s and one 1 and so on Today binary is the cornerstone of computer programming where every number can be represented by a series of switches that are either on 1 or off 0 Breakthrough Mechanical calculators were invented making calculations easier and more likely to be accurate This was important both in science and trade This table shows the numbers 1 to 10 in the decimal system we use every day and how they are written in the binary system 9
