But it is a scientific theory based on repeated observations, experiments,measurements and discoveries.

VOA: special.2009.12.01

They're actively engaged in the material, actually seeing the phenomena, by making measurements of real world experiments.

学生们能自主地参与到物质中，看见真切的现象，通过对真实世界实验,做出测量。

麻省理工公开课 - 媒体、教育、市场课程节选