The student pilot remained in the traffic pattern for his first solo flight and completed one uneventful touch-and-go landing. On the second landing approach, the airplane floated during the landing flare. The student pushed the control yoke forward and the nose gear of the airplane struck the ground. The airplane bounced, entered a porpoise, and the nose gear collapsed. During the landing sequence the airplane sustained substantial damage to the firewall. The pilot said there were no mechanical malfunctions or failures.