On June 4, 2004, at 1510 central daylight time, a Cessna 172P, N50923, nosed over while landing on runway 04L (3,202 feet by 75 feet, asphalt) at the Timmerman Airport, Milwaukee, Wisconsin. The certified flight instructor (CFI) and the student pilot were not injured. The airplane was substantially damaged. The 14 CFR Part 91 instructional flight was operating in visual meteorological conditions without a flight plan. The local flight originated about 1430. The CFI stated the purpose of the flight was to practice takeoffs and landings. He stated the accident occurred on the fourth landing of the flight. The CFI stated the student flew the traffic pattern and was lined up with the runway centerline using a slight crab angle to the right. He stated the airplane began drifting to right during the landing flare. He recalled hearing the student say "runway lights." The CFI stated he called for a go-around and the throttle was advanced to full power. The CFI stated he felt the airplane "mushing" so he pushed the nose forward to maintain airspeed. He stated he anticipated that the nose would lift because they had 30 degrees of flaps extended. He continued to state that the airplane then yawed sharply to the left, hit the ground, and flipped inverted. The CFI stated he shut off the mixture, fuel selector, magnetos, and master switch prior to exiting the airplane. The CFI stated that during the go-around the airplane required an "inordinate" amount of right rudder to keep the nose straight.