The classic barometer joke

A physics student had time to kill at the end of an exam, and decided 
to have some fun with the extra-credit question: "You are given an 
accurate barometer, how would you use it to determine the height of a 
skyscraper ?"

1: He answered: "Go to the top floor, tie a long piece of string to 
the barometer, let it down 'til it touches the ground, and measure the 
length of  the string".

The examiner wasn't satisfied, so the professor decided to interview 
the guy:

"Can you give us another method, one that demonstrates your knowledge 
of physics ?"

2: "Sure.  Go to the top floor, drop the barometer off, and measure 
how long before it hits the ground......"

"Not quite what we wanted.  Care to try again ?"

3: "Make a pendulum of the barometer, measure its period at the 
bottom, then measure its period at the top...."

"...another try ?..."

4: "Measure the length of the barometer, then mount it vertically on 
the ground on a sunny day and measure its shadow, measure the shadow 
of the skyscraper...."

"...and again ?..."

5: "Walk up the stairs and use the barometer as a ruler to measure the 
height of the walls in the stairwells."

"...One more try?"

6: "Find where the janitor lives, knock on his door, and say 'Please, 
Mr. Janitor, if I give you this nice barometer, will you tell me the 
height of this building?"



There are many more ways, for instance:


From: eaobrien@ebi.ac.uk (Emmet O'Brien)
7: To which the less polite alternative is to threaten to wallop the 
caretaker with the barometer, unless he tells you how high the 
building is.


From: Phil Gustafson <phil@rahul.net>
The just-released book, "Expert C Programming (Deep C Secrets)", Peter 
van der Linden, SunSoft/Prentice-Hall, ISBN 0-13-177429-8, lists 
twenty-one (21) more or less useful ways to measure the height of a 
building with a barometer.

8: Use the barometer as a paperweight while examining the building 
plans.


From: ljz@panix.com (Lloyd Zusman)
9: Tie a long cable to the barometer and lower it from the top of the 
building to the ground, and then measure the length of the cable.


From: gt4495c@prism.gatech.edu (Giannhs)
10: Use a barometer to reflect a laser beam from the top, and measure 
the travel time.

11: Track the shadow of the building, positioning a barometer on the 
ground every hour.

12: Create an explosion on the top, and measure the time for the 
pressure depression indicated on the barometer.