The pilot reported that he had flown to a remote lake to practice touch-and-go landings, in a float-equipped airplane, on glassy water. On his first landing, the airplane touched down in a slight nose-low attitude, and the right float struck the water. The airplane subsequently nosed over, sustaining substantial damage to the wings, and right lift strut. The pilot reported no preaccident mechanical malfunctions or failures that would have precluded normal operation.