To carry out experiments into classrooms, in order to test hypothesis or new learning tools needs to perform recurrent complex and time-consuming tasks. We propose means for setting up web based experiments by distinguishing the experimentation perspective and the learning perspective. This paper presents the experimentation platform we have developed for the Kaleidoscope Network of Excellence (NoE) "Shared Virtual Laboratory" action. This platform, called "LearningLab", gives a concrete expression of our proposal, and provides researchers with useful tools for each phase of an experiment. The usability of this platform has been put to the test with two experimentations about electricity learning.