Fermi Problems

The types of problems shown below are known as Fermi problems, after the famous Italian physicist Enrico Fermi.

Two solved examples can be studied by clicking here.

1. Estimate the number of ping-pong balls that can fit in the classroom. Discuss your model and any assumptions you make in great detail. Calculate the upper and lower bounds for your answer. How accurate is your model (in other words, what percent error do you expect in your estimate)? Class Notes

2. Estimate the amount of each of the ingredients required to make the concrete used in all the interstate highways in California.

3. Estimate the distance (in kilometers) that you walk and run during a typical week while attending classes. Include all activities each day.

4. What is the mass in kilograms of the student body at San Jose State University?

5. How many golf balls will fit in a suitcase?

6. How many gallons of gasoline are used by cars each year in the United States?

7. How high would the stack reach if you piled one trillion one-dollar bills in a single stack?

8. Approximately what fraction of the area of the continental United States is covered by automobiles?

9. How many hairs are on your head?

10. In the 1989 Loma Prieta earthquake in California, approximately 2 million books fell off the shelves at the Stanford University library. If you were the library administrator and wanted to hire enough part-time student labor to put the books back on the shelves in order in 2 weeks, how many students would you have to hire? (You may assume that the books just fell off the shelves and got a bit mixed up but books in different aisles did NOT get shuffled together.)

11. A floppy disk for a computer stores information by magnetizing small regions of the disk. For a typical floppy disk, estimate the area of the disk that corresponds to a single bit of information. (Remember: the storage capacity of a disk is cited in bytes where 1 byte = 8 bits.)

12. Maria Elena is an Engineering student at San Jose State University taking a "normal" load (for Engineers!) and paying full tuition. Estimate how much she is paying for each hour of class time she spends with an instructor over one semester.

13. Assuming one Santa Claus visits all Christian children on Christmas, how fast would he have to travel?

14. How likely is the existence of an extraterrestrial civilization?

15. Estimate the cost of lighting your classroom during the entire year.