GHS:
They are basically primary colors in gooey form that the child can squish in the bag to make secondary colors. If you don't expect too much (it will entertain but not for a long time), it's a fun project. My dd played with the bags for a few minutes at a time across 3 days, then we tossed the bags. The cooking/stirring part is a little tedious. I did the prep while the kids were sleeping, would be tricky otherwise.
To make color bags, you need:
1 cup corn starch
1/2 cup sugar
4 cups cold water
food coloring
3 gallon locking bags
put dry ingredients in a medium size pot, slowly add cold water, stir together, then heat over medium heat for approximately 10-15 minutes (may vary based on your stove), stirring continuously. don't let it overheat or boil.
when it thickens like pudding (felt like this would never happen but it does), remove from heat, stir for 1 more minute.
Let cool for about a half hour, divide mixture into three bowls.
Add drops of color to bowl, so you end up with a red, blue, yellow.
Pour half of each bowl into a bag, creating a bag with blue/red, blue/yellow, red/yellow.
Firmly seal bag, tape closed if you are concerned (I wasn't).
Let kid pound/squish/step on bag etc.
