The "Green Classroom" in the Botanical Garden of the University of Ulm is a learning forum outdoor school that is used by about 2500 school students annually. Its educational concept is based on experiential learning and is geared towards expanding students' biological knowledge and developing positive attitudes towards small animals and invertebrates such as insects. In the first study, 104 secondary-school students (49 who had previously visited the "Green Classroom") were asked to write an essay about small animals such as insects. Students who had visited the "Green Classroom" before showed more biological understanding and portrayed more positive emotions towards small animals, and had fewer misconceptions than their peers. In the second study, 121 students (grades 3 and 4) were asked to draw a picture of a forest as a habitat; 65 of these students had previously visited the "Green Classroom" (test group). Students of the test group drew more smaller types of animals in their pictures and furthermore more different species than the control group.