Water play is a great sensory activity. Fill mixing bowls with water and provide children with egg beaters, whisks, and mixing spoons. You can also add glitter, ice, bits of paper, food coloring or a few drips of dish soap.
This activity allows them to explore the scientific qualities of the objects in the water. They will see that when you mix the red water with the blue water it turns purple, they may also notice that you can not undo what they have done.
But when they mix the pieces of paper into the purple water they can still extract the paper. This will help them learn that everything will react in a different way as well as the qualities that cause them to react the way they do.