At approximately 0710 Central time, the airplane was substantially damaged during a hard landing. Visual conditions prevailed at the time of the accident. The flight instructor and student pilot were not injured. As a front approached the airport, instruction on crosswind landings was being conducted. When on a 1 mile final approach, the airplane encountered turbulence and the airspeed dropped. Short of the runway threshold, the airplane began sinking and the instructor pushed the nose down “to gain some lift,” then pulled up to flare. The airplane continued to sink, struck the runway and bounced. The airplane touched down again and skidded off the left side of the runway onto the grass. It struck a ditch and the nose gear collapsed.