Make Sand! Mix 4 cups of sand and 2 cups of cornstarch in an old pot (it may scratch!) Pour 2 cups of water into the mixture and heat on the stove over low heat. Keep stirring until the sand is close to the consistency of very thick mud, then cool it in another bowl. When it has completely cooled place the sand on a piece of newspaper outside. Have your child kneed the mixture until it feels like Play-Doh, when it's ready, they can build a sandcastle on a piece of cardboard. If the sand starts to dry out, have them wet their hands and continue. Before the sand dries, they can add shells or other beachy touches.