Measure baking soda into a large mixing bowl.
Slowly pour the vinegar into the bowl.
When the mixture stops bubbling whisk to combine well.
Add the 2 tablespoons of corn syrup and cornstarch to the bowl.
Whisk well the mixture well.
Transfer some of the mixture to a small spouted measuring cup.
Carefully pour the mixture into each compartment of the ice cube trays.
Squeeze drops of food coloring into each compartment mixing colors following to coloring chart.
Use a tooth pick, skewer or Popsicle stick to mix the colors.
Once the food coloring is mixed in set trays in a safe area to allow to dry complexity. May require up to 48 hours to dry completely.
Once dry use your homemade watercolor paints just like you would store bought watercolor paints.