Estimates and Fermi Calculations
1.5 Estimates and Fermi Calculations
By the end of this section, you will be able to:
- Estimate the values of physical quantities.
Estimation means using prior experience and sound physical reasoning to arrive at a rough idea of a quantity’s value. Because the process of determining a reliable approximation usually involves the identification of correct physical principles and a good guess about the relevant variables, estimating is very useful in developing physical intuition.
|Give an estimate of the number of steps in the stairway of a ten-story building.|
|Very roughly, how thick is one page of a textbook?|
|(a) 1 × 10-5 m|
|(b) 1 × 10-4 m|
|(c) 1 × 10-3 m|
|(d) 1 × 10-2 m|
|(e) 1 × 10-1 m|
Consider how you would answer this question. Then bring this to class for a group discussion.
Estimate how many tennis balls it would take to fill our classroom (or any room you happen to be in).