On April 26, 1996, approximately 0830 central daylight time, a Cessna 172P, N5215K, was substantially damaged during a hard landing at the Denton Municipal Airport, Denton, Texas. The student pilot was not injured. The airplane was rented from Centerline Aviation, Inc., by the pilot for the instructional flight conducted under Title 14 CFR Part 91. Visual meteorological conditions prevailed and a flight plan was not filed. The local supervised solo flight departed Denton approximately 5 minutes before the accident. According to the student, after completing three landings with the flight instructor on board, he departed on his second solo flight. At the completion of his first circuit of the traffic pattern, the student "made a bounced landing" and the airplane "porpoised." The propeller struck the pavement and the firewall sustained damage.