This activity can be typically used to introduce students to NOS.
Students are presented with a can demonstration that supposedly represents a natural phenomenon. While demonstrating, students are asked to make observations and inferences on how it works.
A discussion on NOS deals with the distinction between observation and inference. It will be pointed out that scientists cannot see what is going on most natural phenomena like the can demo. Therefore, scientists are supposed to explain the phenomena with observations. Scientific inquiry processes involve scientists' observations and inferences to understand how the natural world works. Scientific knowledge is also inferential entities (e.g., gravity, atoms, temperature, radiation, etc.) which scientists cannot directly observe.