402 years ago today, on June 19, 1623 (May 22, 1623), the French mathematician, physicist, and thinker Blaise Pascal was born. He was born on June 19, 1623, in Clermont-Ferrand, Dom-Hill, France. Pascal received no formal schooling. His mother died when he was 4 years old, and he was educated and raised by his highly educated, government official father and two sisters. His father was a respected mathematician, and under his careful education, Pascal became proficient in Euclidean geometry at an early age. He independently discovered the first 32 theorems of Euclid, and the order was completely correct. After discovering alone at the age of 12 that "the sum of the inner angles of a triangle is equal to 180 degrees", he began studying mathematics from his father. In 1631, Pascal moved to Paris with his family. His father found Pascal very promising, and at the age of 16, he was full of interest in taking him to the academic activities of the Paris Group of Mathematicians and Physicists (the predecessor of the Paris Academy of Sciences), which opened his eyes. At the age of 17, Pascal wrote a very high-level article on mathematics, "The Theory of Conic Truncation", which was the result of his classic work on comprehensive projective geometry by Dezalge. In 1631, Pascal's family moved to Paris. Ekinina himself educated Pascal and often talked with leading Parisian geometers such as Maran Mason, Gassandi, Dezalgo, and Descartes. At this time, Pascal showed great talent in mathematics. At the age of 11, Pascal wrote an essay on the relationship between vibration and sound, which caused Ekinina to fear that his son would interfere with the study of Greek and Latin, so he was forbidden to study mathematics until the age of 15. One day, Ekinina found that Blaise (then 12 years old) used a piece of coal on a wall to independently prove that the sum of the angles of a triangle is equal to two right angles. From then on, Pascal was allowed to study Euclidean geometry. Pascal was particularly interested in Dezalgo's writings. Under the influence of De Zalger's ideas, Pascal wrote "On Conic Curves" at the age of 16. Most of the book has been lost, but one important conclusion has been preserved, namely "Pascal's Theorem". Descartes greatly appreciated the book, but could not believe that it was written by a 16-year-old boy. In 1641, Pascal moved to Rouen with his family. While helping his father with tax calculations between 1642 and 1644, Pascal invented the adder, the first calculator in the world, which is now on display in French museums. In 1610 he accepted religious teachings, but still devoted himself to scientific experiments. Between 1653, Pascal concentrated on the study of vacuum and hydrostatics, achieving a series of major results. In 1647, he returned to live in Paris. He carried out a large number of experiments based on Torricelli's theory. The experiment in 1647 caused a sensation in Paris. He himself said that the guiding principle of his experiments was to oppose the traditional concept that "nature hates vacuum". From 1647 to 1648, he published a paper on the problem of vacuum. In 1648, Pascal conceived and carried out experiments to measure the atmospheric pressure at different altitudes in the same area, and found that the atmospheric pressure increased as the altitude decreased. During these years, Pascal made new discoveries in his experiments, and made many major inventions, such as the invention of the syringe, the hydraulic press, and the improvement of Torricelli's mercury barometer. From 1649 to 1651, Pascal and his collaborator Pierre (Perier) made detailed measurements of atmospheric pressure changes at the same location, becoming pioneers in the use of barometers for weather forecasting. In 1651 Pascal began to summarize the results of his experiments, and by 1654 he wrote "Essays on Liquid Balance and the Weight of Air", which was officially published in 1663. After this, Pascal turned to theological studies, and in 1655 he entered the theological center of Pitterreuer. Starting from skepticism, he believed that both sensory and rational knowledge were unreliable, and thus concluded that faith was above all else. Before 1646, Pascal's family were Catholic. Due to an illness of his father, he was exposed to a more esoteric way of religious belief, which had a great impact on his later life. Pascal corresponded with the mathematician Fermat, and together they solved a problem sent by an upper-class gambler and amateur philosopher. He couldn't figure out why he kept losing money when he threw three dice in a certain combination. In the process of solving this problem, he laid the foundation of modern probability theory. During his short life, he made many contributions, most notably in mathematics and physics. In 1646, he made a mercury barometer to test the theories of the Italian physicists Galileo and Torricelli. He repeatedly performed experiments on atmospheric pressure on a mountain top overlooking Clermont-Ferrand in Paris, paving the way for the study of hydrodynamics and hydrostatics. In order to improve Torricelli's pneumatic juice, he invented the syringe on the basis of Pascal's law and created the hydraulic press. His research and writings on the problem of vacuum further enhanced his reputation. He was physically weak from an early age, and he was plagued by diseases due to overwork. However, it was during his medical leave from 1651 to 1654 that he carried out intense scientific work and wrote many treatises on liquid balance, the weight and density of air, and the arithmetic triangle, the latter of which became the basis of probability theory. Between 1655 and 1659, he also wrote many religious works. In his later years, it was suggested that he publish the results of his research on the whorl line, so he became immersed in scientific interest, but from February 1659, his illness worsened, preventing him from working normally and settling for a pious religious life. Finally, he died of great illness. Pascal died on August 19, 1662, at the age of 39. Later generations named the unit of pressure after Pascal, referred to as "pa".