http://mathfactor.uark.edu/2011/11/strauss-the-coffee-pot-question/ The Math Factor Podcast Site Fri, 08 Aug 2014 12:52:06 +0000 hourly 1 https://wordpress.org/?v=4.9.25 http://mathfactor.uark.edu/2011/11/strauss-the-coffee-pot-question/comment-page-1/#comment-908 Tue, 06 Dec 2011 01:32:59 +0000 http://mathfactor.uark.edu/?p=1348#comment-908 the coffee evaporates.
how much of a factor this is obviously depends on the temperature.
OR
with conical shaped (narrower at top) coffee pots half the volume will be concentrated near the bottom so it may look emptier than it actually is…
OR
of the people who want a cup of coffee, only a subset of those people will want it badly enough to be willing to make a new pot if they see that there’s only one cup left. so fewer people go for coffee when there’s only one cup left (or i guess less than 2)


 

]]> http://mathfactor.uark.edu/2011/11/strauss-the-coffee-pot-question/comment-page-1/#comment-906 Wed, 30 Nov 2011 21:14:17 +0000 http://mathfactor.uark.edu/?p=1348#comment-906 My own explanation is about this simple, but is in a different vein… I’ll save my answer for a while! Thanks Harry! And great additional question!

]]> http://mathfactor.uark.edu/2011/11/strauss-the-coffee-pot-question/comment-page-1/#comment-905 Wed, 30 Nov 2011 21:09:41 +0000 http://mathfactor.uark.edu/?p=1348#comment-905 It sounds like there is a quasi-mathematical explanation out there for the empty coffee pot phenomenon. What I have to say isn’t that clever, but it is based on actual experience with communal coffee pots.
The main point is that coffee gets stale as it sits, and stale coffee can taste pretty bad. Therefore there is not motivation for anyone who sees an empty pot to make a fresh one unless s/he actually wants a cup. So whoever takes the last cup isn’t doing anyone any favors by making more. Also, I don’t know if anyone checks in on your department’s tea room – departmental admins are probably a luxury at universities these days – but, if so s/he might just dump a pot that was obviously old and stale.
Random notes. Since anyone who makes a pot is going to take a cup, no one coming into the room will ever see a full pot. And if several people come in together to get coffee, which does happen, there you go. There are probably some specific times in the day (like right after lunch) when there is an abnormal run on coffee, and that can draw the pot down. Finally, the painful truth is that a lot of people are just too lazy, or more kindly in too much of a hurry, to make a fresh pot, so the pot will stay empty even if coffee was desired.
Since I couldn’t provide a truly clever coffee answer, I’ll present you with a good coffee question once posed by someone much cleverer than I: Martin Gardner. Suppose you have a cup of hot coffee and put an appropriate amount of cream in it. Assume the cream is a lot cooler than the coffee. Making any reasonable numeric assumptions you want, is the coffee likely to cool off at a faster, equal, or slower rate than if you had left it black?

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