Recent research about the professional development needs as perceived by Italian physics teachers showed that measurement theory ranked last in a list of 17 physics topics. This result may be due to the fact that measurement theory is often taught just at the very beginning of physics courses in high school, wherefore it is considered a topic of mild difficulty; moreover, physics courses are often taught by means of a mainly theoretical approach, i.e., with a limited use of the physics laboratory; consequently, measurement theory is usually seen as a set of rules to be used in scientific calculations mixed with a few metrological definitions that are meant to explain the main characteristics of measurement instruments. This paper aims to show that, despite the apparent simplicity of measurement theory, a number of learning issues characterize such topic, and they should be adequately taken into account in the teaching process. We provide some examples in this regard. Moreover, we propose two simple hands-on learning activity that might be effectively implemented in class in order to introduce 9-10th grade students to some of the main concepts of measurement theory.
