Homological algebra is a widely applicable area of algebra that is concerned with such things as exact sequences, commuting diagrams and homology groups. Many of the basic results of homological algebra can be proved by a technique known as "diagram chasing", and one of the most well known results of this type is the Snake Lemma. According to Charles Weibel's excellent book on homological algebra, the best proof of the Snake Lemma can be found in the following clip from the 1980 film "It's My Turn", featuring the late Jill Clayburgh as the professor.
It is often the case in films that actors are unable to fake certain activities in such a way that the situation seems plausible to someone who knows how to do the activity. A good example of this is when actors pretend to play musical instruments; the results are often embarrassing. However, the professor in this scene does an excellent job, and I would have to prepare my teaching carefully to explain the proof as well as she does.It's My Turn (1980) Snake Lemma #mathematics