Sidewalk Chalk - cooking recipe

Ingredients

3/4 c. powdered plaster of Paris or patching powder
1/4 c. water
4 1/2 inches cardboard tube
waxed paper

Preparation

To make white chalk:
Mix together plaster of Paris and water until the mix is about as thick as toothpaste or mashed potatoes. (If it seems too runny, add 1 tablespoon of plaster at a time until it's thick enough.
If it seems too thick, add a small amount of water.)
Set the cardboard tube upright on the waxed paper.
Spoon the mix into the tube.
Try to pop or push out any bubbles.
Let the filled tube rest upright on the waxed paper for 3 to 4 hours until the chalk has set.
Then, peel off the cardboard (it will be damp).
Let the chalk dry completely for 24 hours.