Celebrating
Π
(3.14159…)
 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!
Solve this
- 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?
- 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.
More circles 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?
Ok, with these thoughts rolling around in
your head, here is an official answer from City of Plano
Utility Technician, Terry Whitehead, who says they’re
round because they’ll 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
More
RESOURCES
What do you think? Email us any other ideas about
manhole covers at info@mindstretchingfun.org.
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