Ordinary sand is free flowing and cannot form a structure that holds its shape. Because it has been coated with a hydrophobic polymer, Magic Sand holds its shape when poured into water and can even be molded into structures. When playtime is done, simply pour off the water and the sand is still dry - it can be used again and again. Observing and playing with Magic Sand is a great way to spark children's curiosity and encourage them to continue studying polymers as they progress in school. Set includes 0.52 oz. each of blue, red and yellow Magic Sand, plus instructions for 3 different experiments. For ages 6 and up.