Teachers and lecturers have used chalk for an eternity and I thank Jesus/Buddha/Elvis that most prefer to use markers and whiteboards these days. Squeaky chalk is only one of many reasons for this transition.
Why does chalk squeak?
Chalk generally squeaks because there are impurities in the chalk. These hard bits of grit scratch against the blackboard much like someone's nails would. The mere thought of it sends a chill down my spine.
How can squeaky chalk be avoided?
There is no simple answer. Typically, the more expensive the chalk the purer it is and therefore the less squeaky it is. Most teachers/schools are poor though and buy robin reliantlow-grade chalk]. Bad chalk is bad chalk but there are possibly a few things that can be done:
- Snap the chalk in two. According to my lecturer this doubles the frequency of the wave produced and therefore should only be audible to dolphins and other aquatic mammals.
- Push down heavier. Hopefully this will rub the grit off quickly and then the lecture can resume squeak free.
- Use the whiteboard. All the rooms at my university have both whiteboards and blackboards and there's really no reason to use chalk. Why would you want to anyway? You get chalk dust all over your clothes.
In this age of cloning sheep and the Internet, do we really need to use squeaky chalk? Or is it just the teacher/lecturer's way of getting back at his or her students?