Celebrate Pi Day — 3.14.12

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“Pi are round, CornbreadR²” —Southern Mathematical Corollary

Today is Einstein’s birthday and the day to celebrate the irrational number for rational minds, Pi (3.141592653…..). According to Wikipedia, the Guinness-recognized record for remembered digits of π is 67,890 digits, held by Lu Chao, a 24-year-old graduate student from China. It took him 24 hours and 4 minutes to recite to the 67,890th decimal place of π without an error.

  Pi represents the relationship between a circle’s diameter (its width) and its circumference (the distance around the circle). This simple relationship is used in equations ranging from Geometry and Trigonometry to Einstein’s Field Equation for General Relativity.

“…The first calculation of pi was done by Archimedes of Syracuse (287–212 BC), one of the greatest mathematicians of the ancient world. Archimedes approximated the area of a circle by using the Pythagorean Theorem to find the areas of two regular polygons: the polygon inscribed within the circle and the polygon within which the circle was circumscribed. Since the actual area of the circle lies between the areas of the inscribed and circumscribed polygons, the areas of the polygons gave upper and lower bounds for the area of the circle. Archimedes knew that he had not found the value of pi but only an approximation within those limits. In this way, Archimedes showed that pi is between 3 1/7 and 3 10/71.” —A Brief History of π, San Francisco Exploratorium

Exploratorium Physicist Larry Shaw founded Pi Day 24 years ago and it has become an international event. What some call “Real Pi Day” will be celebrated on March 14th, 2015 at 9:26:53 AM. These numbers (3/14/15, 9:26:53) correspond with the first 10 digits of pi (3.141592653).

Where to go, What to do:

• Drop by the Exploratorium and join in the festivities.
• Share this day with a child, or the child in you. Click here to connect to the Pi Day web site.
• If you hold up a mirror to a circle, it looks like a circle. If you hold up a mirror to Pi, it spells Pie. ‘3.14’ backwards looks like ‘PIE’
• Enjoy a slice of Pizza Pi today.

The caravan of digits that is pi
does not stop at the edge of the page,
but runs off the table and into the air,
over the wall, a leaf, a bird’s nest, the clouds, straight into the sky,
through all the bloatedness and bottomlessness.
Oh how short, all but mouse-like is the comet’s tail!

—excerpted, Szymborska, Wislawa (2001). Poems New and Collected.

p. 174. ISBN 9780156011464.

Fog City Science

Golden Gate Bridge Fog Horn

It was a foggy day at the bridge today and our “iconic” fog horns were on all shift. Click here for a wonderful explanation of the speed of sound by Shawn Lani of the Exploratorium and a practical way that you can judge a distance in San Francisco by using the sound of the Golden Gate Bridge fog horns.

Listen to Jim Mcknight, Chief Electrician at the Golden Gate Bridge, talk to KCBS about operating the fog horns on the bridge: Golden Gate Bridge Foghorn Operator Enjoys Blasting Signature SF Sound

Click here for a San Francisco Chronicle newspaper article on the fog horns at the bridge.

Bridge Facts

“Steel Stretches! When an engineer makes that statement, his listeners are skeptical. But it does, according to the Bridge engineers. They will tell you that due to the constantly varying winds and temperature at the Bridge site, the Bridge is always moving. Take the cables for example. Engineers say if they were detached and laid out on the ground they would be 21 feet shorter than their hanging length. That measurement is the “stretch” caused by the immense load they support. These factors were an important element in the designing of the Bridge, and the elements enter into them…”  — Official souvenir program, Golden Gate Bridge fiesta : celebrating the opening of the world’s longest single span, San Francisco, California, May 27 to June 2, 1937 

The Outdoor Exploratorium in San Francisco has a telescope 2 miles away where you can see the Golden Gate Bridge rise and fall a total of 16 feet depending on the weather.

Here is a link to an online video that shows you the Bridge Thermometer in action.