You might remember the Magnet/Chalkboard project I posted a little while ago. I had one problem that would not go away. I kept losing the chalk lol. And it's difficult to keep a proper count-down if the chalk is missing.
So, I came up with this, a chalk harness. And all you need to make one is a piece of chalk and some string. So no more wandering chalk and the string can be undone and reused when the chalk wears down to the nub. Tie a loop at the end and put a hook up next to the board and no more lost chalk :D.
Put the end of the string near the end of the chalk.
Loop as illustrated, and slowly tighten to fit snugly around chalk. If you tighten it too fast and hard, the chalk will snap, you can guess how I know that lol.