## Pi has many real-world uses

It’s not all fun and games and feats of memory: Scientists use pi every day to make important calculations, such as determining the volume of a sphere, the area of a circle, and the volume of a cylinder. “Those relationships form the basis for how stiff a structure is, how it will vibrate, and understanding how a design might fail,” says Charles Dandino, an engineer at the Jet Propulsion Lab. “In my career, pi has allowed me to calculate the size of a shield needed to enter the atmosphere of Venus and the size of a parachute that could safely land the Curiosity rover on the surface of Mars,” says another JPL engineer, Anita Sengupta. Another handy tool that makes use of pi? The GPS system in your car and smartphone use it to calculate specific locations on Earth.

Check out these 10 fascinating things captured by Google Earth.

## Do a magic trick to calculate pi

To try this easy activity known as Buffon’s Needles, you need a large sheet of paper, at least 30 toothpicks, a ruler and a pen. Using a toothpick to determine the distance between them, draw a series of parallel lines on your paper. Then throw the toothpicks onto the paper at random.

Next, take away any toothpicks that are only partially on the paper, or that didn’t land on the paper at all. Count how many are left on the paper. Also, count how many cross a line.

Divide the total number of toothpicks by the line-crossing toothpicks. Now multiply by two, and you should get pi!

## Pi is a movie star

Pi has made several significant appearances in pop culture. Most notably, there is an entire film about it, called *Pi: Finding Faith in Chaos*. The 1998 film, which won an Independent Spirit Award for screenwriter Darren Aronofsky, is admittedly a bit of a downer, as it follows a tormented mathematician trying (and failing) to work out the secrets of the universe. In the Sandra Bullock thriller *The Net*, clicking on a pi symbol is what sends Bullock’s character into the confidential government files, and in Alfred Hitchcock’s *Torn Curtain*, the pi symbol is the code that represents the escape network. It’s even vanquished TV villains; in a *Star Trek *episode, Spock outsmarts an evil computer by challenging it to calculate the final digit of pi.