While field trips promote the scientific spirit of students by increasing their ability of observation and discovery in various areas of knowledge, the introduction of ubiquitous technologies, such as sensors and actuators, during the field trips, improves students' motivation and learning. However, the development of systems for this purpose implies to deal with the seamless treatment of the devices heterogeneity, absence of fixed communication infrastructure, dynamics of the computational elements of the environment, and support for user mobility. This paper presents then the development and evaluation of a system, called Ubiquitous Field Classes Inventor (UFC-Inventor), which aims to promote the use of mobile and ubiquitous technologies in field trips. The UFC-Inventor evaluation is performed in two stages: first, with five teachers of natural sciences; and later, during a field trip with seventeen students. Two of the teachers were from higher education (Geology and Animal Science) and three of them from high school (two in Geography and one in Biology). The seventeen students who participated in the case study were undergraduate students in the third year of their Geology course. The results suggest a good acceptance of UFC-Inventor and indicate that its execution occurred correctly.