Boiling water problem

Two stories about the obvious

On the topic of obviousness, there is one classic tale (“I was right. It really is quite obvious” [1]) and two not very famous ones.

Notice the first one .

The professor began to prove to the students a theorem about the equivalence of statements X and Y. Having begun the proof even before the bell rang, he covered three huge boards with beaded handwriting and stopped only when the bell for the next pair had already rung and the audience began to fill with the next stream of students. At this point, he had just finished the proof of “If X then Y.” After examining the fruits of his labors, he said: “The proof in the opposite direction is just as obvious,” and left the audience.

fairy tale The second .

Another mathematics professor once fell silent during a lecture, froze and stood motionless for about fifteen minutes. Finally one of the students dared to disturb him:

- Sir Professor, what are you doing now?

— I was wondering whether what I was going to say next was obvious or not. In the end, I decided that it was obvious, so I won’t say it.

Afterword to “pour the water out of the kettle”

I will omit the story of how mathematicians solve the problem of boiling water if the kettle is already filled and the gas under the stove is already lit (if someone does not know it, let them read the link [2]).

I like the other story better. A student asks a mathematics professor:

— Imagine that you have a stove and a pot of water standing on the next table. How do you solve the problem of boiling water?

Professor's answer:

- First, let's look at the water in the pan. If it boils, then the problem is solved. Otherwise…

1. http://physiclib.ru/books/item/f00/s00/z0000013/st018.shtml

2. www.uni-altai.ru/Resources/MetodTOI/comb/dictonary/chainic.html