1. Enrico Fermi A Modern Renaissance Man FOT 2010 Baltimore Polytechnic Institute Engineering

2. Enrico Fermi, Physicist Fermi was one of the greatest physicists of the 20 th century. He is best known for his leading contributions in the Manhattan Project but his work spanned every field of physics. Baltimore Polytechnic Institute Engineering

3. Early Years In 1901, Enrico was born in Rome to Alberto Fermi, a Chief Inspector of the Ministry of Communications, and Ida de Gattis, an elementary school teacher. As a young boy he enjoyed learning physics and mathematics and shared his interests with his older brother, Giulio. When Giulio died unexpectedly of a throat abscess in 1915 it brought great sorrow to the family and Enrico escaped into his studies. Baltimore Polytechnic Institute Engineering

4. Fermi Electron Theory While in Pisa, Fermi and his friends had a well-earned reputation as pranksters. One afternoon, while patiently trapping geckos (used to scare girls at the university), Fermi came up with the fundamental theory for electrons in solids. Fermi’s theory later became the foundation of the entire semiconductor industry. Baltimore Polytechnic Institute Engineering

5. Fermi Problems Fermi was famous for being able to avoid long, tedious calculations or difficult experimental measurements by devising ingenious ways of finding approximate answers. He also enjoyed challenging his friends with “Fermi Problems” that could be solved by such “back of the envelope” estimates. Laura and Enrico Fermi Baltimore Polytechnic Institute Engineering

6. Fermi Problem Example “What is the length of the equator?” Fermi problems are solved by assembling simple facts that combine to give the answer: The distance from Los Angeles to New York is about 3000 miles. These cities are three time zones apart. So each time zone is about 1000 miles wide. There are 24 time zones around the world. So the length of the equator must be about 24,000 miles The exact answer is 24,901 miles. Baltimore Polytechnic Institute Engineering

7. Ping Pong Anyone? Solving a problem in 60 seconds (individually) Look around the room you are sitting in. Take just 60 seconds to answer the following questions: How many ping-pong balls could you fit into the room? Baltimore Polytechnic Institute Engineering

8. Ping Pong Anyone? Solving a problem in 60 seconds (individually) Look around the room you are sitting in. Take just 60 seconds to answer the following questions: How many ping-pong balls could you fit into the room? What was your model of a ping-pong ball? What was your model of the room? Baltimore Polytechnic Institute Engineering

9. Ping Pong Anyone? Solving a problem in 60 seconds (individually) Look around the room you are sitting in. Take just 60 seconds to answer the following questions: How many ping-pong balls could you fit into the room? What was your model of a ping-pong ball? What was your model of the room? What other simplifications or assumptions did you make? Baltimore Polytechnic Institute Engineering

10. Fermi Problems Open ended problem solving. Thought process is more important than calculating exact answer. Steps in solving Fermi problems – Determine what factors are important in solving problem – Estimate these factors – Use dimensional reasoning to calculate a solution

11. Fermi Problems What do Fermi Problems have to do with engineering – Engineers have to solve open ended problems that might not have a single right solution – Engineers have to estimate a solution to a complicated problem – Engineers have to think creatively

12. The Fermi Paradox The extreme age of the universe and its vast number of stars suggest that if the Earth is typical, extraterrestrial life should be common. Discussing this proposition with colleagues over lunch in 1950, Fermi asked: "Where is everybody?” We still don’t have a good answer to Enrico’s question. Baltimore Polytechnic Institute Engineering

13. Homework- Due tomorrow The physicist Enrico Fermi enjoyed posing questions like these to his students and colleagues. Pick one part (either a or b) from each of the following two questions, and make the best possible estimate for the situation. Your answer will be a combination of several quantities. Be sure to specify what assumptions you have made in arriving at your estimate. Baltimore Polytechnic Institute Engineering

14. Homework continued 1. a. How long do you think it would take you to eat your weight in food? or b. What is the weight of all the trash produced in your house in a year? Write all your assumptions and calculations Baltimore Polytechnic Institute Engineering

15. Homework continued 2. a. How many hot dogs do you think are sold in a baseball season at Oriole Park? or b. How many times does a person's heart beat in a lifetime? Write all your assumptions and calculations Baltimore Polytechnic Institute Engineering