Oil and water never mix. We used this fact or tested this fact, whatever it was, we made some interesting painting and had fun. We mixed in different color tempera paint with oil in different bowls. And then we filled half of a pan with water. Then we took paint in the fingers and dropped them on the surface. We also used the back tip of paint brush to paint gently across the water surface. It was very interesting to do this and watch the colorful paint floating on the surface of water. We also spread sheets of paper over the water and got some paintings. Though I wanted the paper to only float on the surface we ended up immersing it.