Here is a basic sidewalk chalk paint recipe I found on the Kiddio blog. The colors dry very bright and leave a bit of residue after washing away, but it fades pretty quick after a few days of sunlight.
You need: box of cornstarch, food coloring (liquid), water, some containers
In container add 1/4 cup cornstarch, then 1/4 cup water, about 5-10 drops of food coloring. It is difficult to mix at first, but it will suddenly come together (remember to put cornstarch in container first). My boys really enjoyed this, check out how laid back Hudson was with his painting….don’t exert too much energy there kid!