The main goal of this study was to obtain insight about the factors that influence students' ability to learn during a field trip, in order to improve the planning and execution of learning field trips. The study was conducted in the context of a 1-day geological field trip for high school students in Israel. Three domains were tested by observations and questionnaires: (1) the nature of the learning activities during the field trip; (2) student attitudes to the field trip in which they had participated; and (3) changes in knowledge and attitudes following the field trip. Data were collected from the students, the teacher, and an outside observer before, during, and after the field trip. The research population consisted of 256 students in grades 9-11. Statistical procedures (t-test and analysis of covariance) were used in order to determine the effectiveness of age and preparedness on student performance during the field trip. It was found that the age variable had little significant influence and the preparedness variable was significantly more dominant. The learning activity of students who were prepared by studying a short unit that focused on cognitive preparation was significantly better than that of the other students. In order to determine variables that affect learning during a field trip, a multiple regression analysis was conducted. The regression included 22 different independent variables, which were grouped in three categories: background, pre-field trip, and field trip variables. Three variables were connected to student characteristics prior to the field trip and include knowledge level and type, acquaintance with the field trip area, and psychological preparedness. All together they define a "novelty space" for the student getting out on a field trip. It was concluded that reduction of this novelty space before the field trip can enhance learning performance during the field trip. (17 references) (KR)