On April 3, 1999, about 1330 Eastern Standard Time, N2472N, a Piper PA-38-112, was substantially damaged when it impacted the ground during takeoff from Harris Airport, Lincoln University, Pennsylvania. The certified flight instructor (CFI) and student pilot were not injured. Visual meteorological conditions prevailed and no flight plan was filed for the instructional flight conducted under 14 CFR Part 91. The CFI stated in a telephone interview that he and the student pilot had been performing touch and go landings, and emergency procedures at the Harris Airport. After touching down on "Runway S", a 1,500-foot long grass runway, the student pilot increased the throttle, and abruptly pulled back on the yoke. As the airplane climbed to about 20 feet above the runway, the stall warning horn began to sound, and the airplane became "mushy". The airplane began to settle back to the ground, and the CFI took over the controls. The airplane then impacted the ground, about 150 yards from the end of the runway, nose first, and sheared off the left wing.