PASCAL

Blaise Pascal, a Frenchman who passed away at the age of just thirty-nine, his time on earth unfortunately cut short by poor health, made significant contributions to the fields of mathematics and science – this, despite his abandonment of scientific study in favour of religious devotion in 1655.

During his twenties Pascal spent a large amount of time undertaking experiments in the field of physics. The most important of these involved measuring air pressure. An Italian scientist, Evangelista Torricelli (1608 – 47), had argued that air pressure would decrease at higher altitudes. Pascal set out to prove this by using a mercury barometer. He took initial measurements in Paris and then, at the 1200m-high Puy de Dome in 1646, confirmed in no uncertain terms that Torricelli’s speculation was true.

• Pascal’s Law

More significantly, though, his studies in this area led him to develop Pascal’s Principle or Law, which states that pressure applied to liquid in an enclosed space distributes equally in all directions. This became the basic principle from which all hydraulic systems derived, such as those involved in the manufacture of car brakes, as well as explaining how small devices such as the car jack are able to raise a vehicle. This is because the small force created by moving the jacking handle in a sizeable sweep equates to a large amount of pressure sufficient to move the jack head a few centimetres. Applying the lessons of his studies in a practical way, Pascal went on to invent the syringe and, in 1650, the hydraulic press.

• Child prodigy

In spite of these developments, however, Pascal is probably better remembered for his work in the area of mathematics. It was here that he showed his genius from an early age. For example, having independently discovered a number of Euclid’s theorems for himself by the age of just eleven, he went on to master The Elements, the great mathematician’s definitive text, a year later. When he was sixteen he published mathematical papers which his older contemporary Descartes at first refused to believe could have been written by someone so young. In 1642, still only nineteen, Pascal began work on inventing a mechanical calculating machine which could add and subtract. He had finished what was effectively the first digital calculator by 1644 and presented it to his father to help him in his business affairs.

• Theory of Probability

It was not until later in his short life, around 1654, that Pascal jointly made the mathematical discovery which would have the most impact on future generations. It had begun with a request by an obsessive gambler, the Chevalier de Méré, for assistance in calculating the chance of success in the games he played. Together with Pierre de Fermat, another French mathematician, Pascal developed the theory of probabilities, using his now famous Pascal’s Triangle, in the process. As well as its obvious impact upon all parts of the gambling industry, the importance of understanding probability has had subsequent application in areas stretching from statistics to theoretical physics.

The SI unit of pressure – the pascal – and the computer language, Pascal (named in honour of his contribution to computing through his invention of the early calculator), are named after him in recognition of two of his main areas of scientific success.

Seven of the calculating devices that he produced in 1649 survive to this day.

• Pascal’s Wager

Like many of his contemporaries, Pascal did not separate his science from philosophy, and his book Pensees, he applies his mathematical probability theory to the perennial philosophical problem of the existence of God. In the absence of evidence for or against God’s existence, says Pascal, the wise man will choose to believe, since if he is correct he will gain his reward, and if he is incorrect he stands to lose nothing, an interesting, if somewhat cynical argument.