英语课程计划-Pi Day（在线收听）

Pi Day is on March 14. This is the day when mathematicians and geometry enthusiasts around the world get together and celebrate the mathematical constant of Pi. There are two good reasons to hold Pi Day on March 14. The first is that in the American date format, it is 3/14 and Pi, to two decimal places, is 3.14. The other reason is that March 14 is Albert Einstein’s birthday, and he knew a thing or two about numbers. Pi Day started in 1988 at the San Francisco Exploratorium. The museum staff walked around the circular spaces in the building eating fruit pies. Cherry and apple pies have very little to do with Pi, unless you want to calculate the circumference of your fruity treat.

Pi is a letter of the Greek alphabet. The symbol was first used in mathematical calculations in 1737 by the Swiss mathematician Leonhard Euler. It is used for the ratio of the circumference of a circle to its diameter. Computers have calculated Pi to over one trillion digits. It has countless numbers of digits. Perhaps more impressive is the feat of British autism sufferer Daniel Tammet. He holds the European record for reciting Pi from memory to 22,514 digits in just over five hours. He also suffers from a condition in which he sees numbers as colours. He says Pi is particularly beautiful. The worlds of science, engineering and mathematics would be lost without it. Celebrate today with your favourite pie!