For each color you will need
1/3 cup cornstarch
1/3 cup water
4-6 drops of food color
How to
In a plastic cup (or muffin tin) mix cornstarch, water and food color.
Repeat for each color you want.
Use a paint brush or your finger to color on the sidewalk
HAVE FUN
For each color you will need
1 cup flour
1 cup water
1/2 cup shaving cream
food color
Gallon freezer bag
Plastic Squirt bottle
How to
Mix flour and water together in a freezer bag. Mix till there are no clumps.
Add 8-10 drops of food color and 1/2 cup of shaving cream, then mix it all together.
Cut a small corner of the bag so you can squeeze the content into the bottle.
HAVE FUN