This article presents a part of the Inter-Tetra project. This study firstly reviews the literature on conceptions of experiments in didactics of math and didactics of physics to design questionnaires to survey the conceptions of experiments in teaching physics and teaching math in Vietnam. Thereafter, the survey has been conducted among the math and physics pedagogical students in the Hanoi National University of Education (HNUE). The results of the survey have revealed the similarities and differences of the concepts of an experiment in teaching math and physics. In addition, this study also discusses the causes and consequence of the similar and dissimilar concepts of experiments.