Experiences

Angular momentum

Massimo Amato

Italy

High Secondary School

Physics

Teaching in class

Direct

The chapter, as presented, of the angular momentum is often less explained. This topic should be discussed at the end of the third year, but usually it is not studied because it is the last in order of time and sometimes it is more complicated in its full understanding. It is a very large section about the rotational dynamics, centre of mass, moment of inertia, rotational kinetic energy, angular momentum and gyroscopic effect.
The first few times I faced this issue I tried to follow the text without dwelling too much to allow students to have a clear and easily verifiable scheme.
But who studied could not remember the formulas and did only some exercises more or less complicated, depending on the time available.
Who took the topic in a superficial way did not remember anything of that.
Since time is always short, I decided to approach the study of the angular momentum with an overview of the effects that it produces, or giving a name to the experiments and especially evidence of facts known since they were kids, like the whirligig, hold a basketball on a finger, how the bicycle stand on, the dancers, trampoline jumpers, how they could use the gyroscopic effect into aircraft, satellites and smartphones.
This knowledge is accessible to any class, does not involve the use of laboratory and it can be easily constructed by the students themselves.
The effect of this approach was to obtain a dual result: enthuse students with something known but now easily explained, remember the experiments without apparent effort, allow a study of the formulas in a mechanical simple way, because now the reason of their validity is known.