Whether they are in the bath, splashing away, or keeping nice and dry at the edges, young children will agree that the bath tub makes a really cool "laboratory" for carrying out experiments that are gallons of fun. Do they want to know why some toys sink, but a rubber duck always floats? Do they know how a submarine works? Why cream crackers get mushy in water? How does an ice cube rise to the surface? When does water move upwards on its own? Science basics are a joy when you're making a "wave machine", a water cannon that blasts mind-boggling explosions of liquid, and zippy hydroplanes. Or, peering through a periscope, preparing the perfect bubble solution, and whipping up a batch of water glue.