Many physics professors have difficulties to know and assess in real time the learning of the students in their courses. Nevertheless, today, with Internet and the new technology devices that the students use every day, like smartphones, such tasks can be carried out relatively easy. The professor pose a few questions in "Socrative," the students answer them by means of the Smartphone. In this way, the professor knows what students learned and can promote the cooperative learning joining students who think differently, with the purpose to give them chance to discuss their answers and argumentations and, eventually, to improve both answers and arguments. In this article, we present the results of an initial feasibility study of using "Socrative" and smartphones carried out with prospective teachers. The effects on the students were: they help them to understand concepts; they facilitate the argumentation and the exchange of opinions. In addition, the use of this technology is, generally, easy for students and turns out to be interesting in the classroom. In conclusion, by using efficiently "Socrative" and students' smartphones, professors might achieve jointly three different goals: real-time assessment of the students' learning, motivation of the students and increased opportunities for active learning.