Directions Fill the bathtub or sink with water. Set all the objects nearby within your child’s reach. The object of this activity is to see which objects float and which ones don’t. Some may float for a while and then sink. Some small objects may sink immediately, while some large objects stay floating. Make a guessing game out of it. Before putting the item in the sink, guess if it will sink or float. Ask your child questions: Why do you think this object is sinking? What makes this float? Then notice if the water goes up on the side of the sink when an object is added. Let your child hold each object in his hand, determining if it is heavy or light. Have him hold one object in each hand and say which is heavier.