It is unknown whether Einstein was subject to Blackboard Stupidity. In this picture, he appears to be far enough from the blackboard that BS effects should be minimal. Image: public domain, via Wikimedia Commons

I just finished my first week teaching after a few years out of the classroom. Whenever I teach, I'm struck by how much detail I need to put in my notes to make sure I don't say something absolutely ridiculous when I'm in front of the class. Even with careful preparation, I sometimes arrive back at my office wondering why I couldn't answer a question that perplexed me in class but suddenly seems so simple. The reason? Blackboards make me stupid, and they probably make you stupid too.

A quick search through stock photos reveals that the intelligence-suppressing powers of blackboards are well documented. But the exact amount that a person's intelligence decreases when he or she stands at the front of a classroom with a blackboard has only recently been determined—by yours truly.

This week, I came up with a preliminary formula that describes the troubling phenomenon of Blackboard Stupidity.

A completely not bogus formula for the Blackboard Stupidity, or BS, factor. Image: Evelyn Lamb.

In this formula:

n=number of students in the class;

s=number of hours of sleep you got last night;

p=number of hours of preparation you did for the class in the past three days;

m="morning factor"=number of hours before noon of the class start time;