Sci-Tech

Pi, the relationship of a circle’s circumference to its diameter, is an irrational number whose digits never end, although it has been calculated to billions of places. Sci-Tech Discovery Center celebrates Pi this month on March 14, or 3.14. Put a candle on a slice of pie at 1:59 p.m. and celebrate Albert Einstein’s birthday, too! 2008 marks Pi’s 302nd anniversary and Einstein’s 129th.

Welsh mathematician William Jones gave Pi its name in 1706, yet Greek scholar Archimedes proved the concept around 200 B.C.

Archimedes	William Jones

To celebrate the meaning of Pi, Sci-Tech Discovery Center worked with PISD to produce a film clip and bookmark to demonstrate its everyday uses. Thanks to Richardson Bike Mart and Alcatel for helping with the project!

* Film clip
* Bookmark (requires Adobe PDF reader)

Solve this:
1. Picture this: an adult riding casually on a bicycle and his small child pedaling furiously to keep up.  What's going on here? How many more revolutions would it take for a 16” wheel to cover 100 yards versus a 27” wheel - gear settings, etc. all else being equal?

2. How many cell towers would be required to cover a city that is 10 miles across and 8 miles wide, taking into account no interferences with other signals? Assume that each tower can cover a 3 mile radius.

Here is another circle to think about:
Why are manhole covers round?

Before discussing possible answers to this question, think about these questions:

* How much does a manhole cover weigh?
* How are the covers removed and replaced?
* How are manhole covers manufactured?
* What is underneath the manhole cover?
* What shapes are the things that go in and come out of the manhole?
* What might walk or roll over the manhole cover? How heavy are those things?

Okay, with these thoughts rolling around in your head, here is an official answer from City of Plano Utility Technician, Terry Whitehead. Terry says they’re round so the technicians will never fall in the hole. Some other answers some have proposed:

* So they can be easily moved by rolling them.
* So they don't require any alignment to place on the hole.
* A round shape distributes weight most evenly.
* They are easier to manufacture.

To further complicate things, manhole covers aren’t round everywhere.  You’ll find square ones in parts of Europe.

Fun Links:
* Find out where your birthday lies in the digits of Pi
* Pictures of Manhole covers. And More Here.

More Resources:
* Pi History from Wikipedia.org