Our context of research is in the field of the CEHA (Computing Environments for Human Apprenticeship) and particularly the DE (Distance Education). It presents a very important facet of experimental teaching. The aim of this paper is to propose a multidisciplinary architecture called CVL@b (Collaborative Virtual L@boratory) for the virtual experimentation on the Web. This architecture allows learners to perform distant practical work (Tele-PW) and experiments using virtual devices in experimental sciences in a collaborative way. The trainers could lead interactive sessions of instructions of Tele-PW using appropriate scenarios, thus using the metaphor of the distant practical worksheet (Tele-PW sheet). CVL@b is a collaborative virtual laboratory for the realization of the Experimental Work (EW). Its design was based on the analysis of the classical laboratories. In order to validate its effectiveness in a real situation, an evaluation was carried by real users. In this article, we first of all present the transition of a conventional Lab to Tele-Labs. Then, we present the CVL@b architecture. After that, we show the selected method for the evaluation of CVL@b also the parameters to be evaluated. Then, we present the got results. We finish with a discussion and a conclusion of this evaluation.