Demonstration of Conservation Sarah, here at age 5¾, demonstrates Piaget’s conservation-of-liquids experiment. First, she examines both short glasses to be sure they contain the same amount of milk. Then, after the contents of one are poured into the tall glass and she is asked which has more, she points to the tall glass, just as Piaget would have expected. Later she added, “It looks like it has more because it’s taller.”

COURTESY OF KATHLEEN BERGER