Fact Check

Erasers Thrown at Clock

Students throw erasers at class clock to advance it, then prof does the same during their final exam.

Published Jan. 27, 2006


Claim:   Students who throughout the semester have advanced the classroom clock by throwing erasers at it inspire their professor to do the same thing during their final exam.


Example:   [Collected via e-mail, 2003]

According to the university rules, if a professor hadn't arrived to a class by 15 minutes past the hour, the class was considered canceled for the day and the students were free to leave — with no penalties for missing a class.

Mounted over the chalkboard of each classroom was a type of wall clock that jumped ahead each minute, in a very noticeable fashion. These clocks were also not constructed in the most sophisticated manner. An enterprising student learned (it's always good to learn things at college) that if you hit the clock with a chalkboard eraser, the clock would jump ahead 1 minute.

So, in a class where the professor wasn't precisely punctual and his students considered him absent-minded, almost daily these students took target practice at the room's clock. A few well aimed erasers, and 15 minutes quickly passed on the clock, and the class dismissed itself.

When the day for the next exam rolled around, the professor strolled into the room on time, passed out the exams, and told class, "You have one hour to complete this test."

The professor collected the erasers from around the room, and gleefully began taking aim at the clock. Within 10 minutes he had successfully jumped the clock forward one hour. "Time's up!"


Origins:   This legend is the embodiment of the ongoing power struggle between college students and professors, and in typical urban legend fashion the question of who is smarter than whom is worked out via displays of trickery. The students, who believe themselves more clever than the one instructing them, apply their smarts not to their studies, but to the problem of finding a way to outwit their professor, a fellow they have concluded is a bit of a dullard. But the teacher proves more than a match for them, first turning a blind eye to their ruse (thus letting them believe they have put one over on him), then turning it against them at a key moment — namely, during their final


The yarn builds upon a widely-believed claim made of almost every college: that all of them have an official policy on their books regarding how long students must await tardy professors, and that the regulation varies depending upon the rank of the instructor involved. While a handful of schools do indeed have an official "wait" rule specifying the number of minutes students must remain in the classroom when their instructor fails to arrive on time, many institutions of higher learning have no rules governing this area, and we haven't found any college with written regulations specifying different wait times based upon instructors' academic rankings, the heart of the "obligatory wait" belief.

In common with the "professor through the transom" legend, the prof in the "thrown eraser" legend is presented as needlessly cruel — he turns his pupils' lighthearted attempt at skylarking into a mechanism that will cause them to fail the class, a response to their wrongdoing that is out of proportion with their offense. (In one variation we encountered in 1999, the professor, after springing a surprise pop quiz on the class, is said to have "amused himself by throwing erasers at the clock," the "amused himself" portion of that account revealing both his sadism and the delight he takes in it.)

The "diabolical professor" is a standard figure found in college legends, so his appearance in this one shouldn't be unexpected. However, this particular legend is about answering in kind — the kids throw erasers at the clock to get out of class, the professor throws them to teach his errant charges that trickery can be a double-edged sword. Similarly, in the "battle of the tape recorders" legend, one side's clever shortcut is answered by a matching end run from the other side, leading to tape decks recording taped lessons and hats looking at hats; while in the venerable "cakes and ale" legend, the student who demands special concessions be made him under the provision of an ancient college regulation finds himself penalized under other aspects of that archaic regulation.

Barbara "the arcane mutiny" Mikkelson

Last updated:   23 June 2011

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