Fermi Questions

I have recently discovered Enrico Fermi again. There are some seminal intellects in Physics; Einstein, Newton, and Galileo are universally known names. I have certainly read and learned much about these 3, but with my new role, Physics Teacher at BCHS, I need to start expanding my data set. Enter Enrico Fermi, and his famous questions.

I know of Fermi's work on the Atomic Pile under the football stadium at University of Chicago. As I was tuning up this summer - researching Physics - I discovered Fermi questions. Evidently the native of Rome( Italy not Texas)was a great teacher as well as a Nobel prize winning researcher.

Physics is often involved in the very large and the very small, and the ability to estimate magnitude is essential. Fermi problems or Fermi questions are exercises in estimation.

Example - How many personal motor vehicles (cars and trucks) are there in Matagorda County, Tx?
I would estimate there are between 16,000-20,000, let's say 18,000 vehicles. Here is how I estimated it. There are about 40,000 residents and a we are a relatively young county so a big chunk of the residents are too young to have cars. Further, we are a relatively poor county and we have many 1 car families.

Actual number of vehicles in Matagorda county according to
http://www.city-data.com/county/Matagorda_County-TX.html
was just under 23,000.

So my estimate was about 78% of the correct number, not too bad. The population I used was a little wrong too, the county had an estimated population of 38,000 in 2005 according to the above site.

Here are a couple of sites with examples and some history.

http://mathforum.org/workshops/sum96/interdisc/sheila1.html

http://en.wikipedia.org/wiki/Fermi_problem