Recently, I read a really amusing order of magnitude
estimation. It was in a so called "guidance-text" for
freshman at the U.Barcelona written by Rolf Tarrach.
Let's see how it goes:
"A man/woman consumes about 3000cal a day. This makes
3000cal 4.184J/cal 1day/86400s = 150 W
That is, one person consumes like a bulb light; ten, like
heater. Bye the way, currently 1 KWh costs about 8$. So,
the dayly energy ingest of a person costs less than 30$.
Why is then meal so expensive?"
I find it a simple but very illustrative example of
inquiry. And also funny.
Another, example was an estimation of the number of
nucleons in the known visible univers (around 10e79).Well,
for this one has to know some basic facts on astrophysics,
namely the number of galaxies seen up to now (10e11), the
number os stars per galaxy (10e11), the mass of a star (10e30Kg),
and finally, the mass of a nucleon(10e-27Kg).
He ends up proposing some other estimation for the students:
-How many cars may circulate in Barcelona?
-What's the net gross income of Spain
-How many piano tuners are in Chicago? (Fermi's famous one)
I realize I must include some for our freshman engineers, and
I wonder which do you present your students. May there be any
book on such things?