Do we write with the sidewalk chalk as much as we wear it once finished?

I'm not sure if there is more sidewalk chalk on our driveway or on Bobby.  I do know for sure that he sneaked in a bite of the yellow chalk before I could stop him.  I once watched a show where a lady regularly ate chalk.....so it can't kill you I guess.  It must not have tasted great because one bite was enough for him.