Sponge experiment!

The question was posed to the children which would absorb more water
a wet or dry sponge? They immersed both sponges in a container of
water and than weighed them. It was explained to the children that
since the wet (damp) sponge weighed more it obviously had absorbed
more water demonstrating that the water molecules in the wet sponge
attracted additional water to them while the dry did not!