Edit to add: in college my first physics class assignment was just random Fermi problems to be answered without looking anything up using top-of-mind round-number assumptions (1, 2, or 5 x 10^n). Things like “How many feathers does a chicken have?” or “How many letters are there in every book in the main campus library?” Second favorite homework assignment I’ve ever been given.
Most people never realize how much the things they know imply about the things they don’t.
Edit to add: in college my first physics class assignment was just random Fermi problems to be answered without looking anything up using top-of-mind round-number assumptions (1, 2, or 5 x 10^n). Things like “How many feathers does a chicken have?” or “How many letters are there in every book in the main campus library?” Second favorite homework assignment I’ve ever been given.
Most people never realize how much the things they know imply about the things they don’t.
What was your first favorite?
It was a 2 sentence problem set from my sophomore year wave mechanics class. Really got the whole class working together.
1) Derive rainbows.
2) What angle does the wake of a boat make with the boat?