After we played with the goop for a while, we added in food coloring. O started to mix it very quickly with her hands, and I slowed her down and showed her how to slowly drag her finger through the food coloring to make a trail of color.
After mixing all of the colors, she decided to add some beach sand to the mixture along with a little more food coloring.
After mixing up the blue sand, she sprinkled it on the beach, so we had a blue polka dotted beach for a little while. While O was swimming the brazen minnows kept biting her mosquito bites, so she took the blue food coloring into the water and threatened to make them blue. Unfortunately, that didn't deter them at all :)