A Teaching Practicum
This is a reaction shot of the class while I am singing. It is important to grab the attention of students at the outset of a lesson, focus them on the topic of the lesson, while putting them in the right frame of mind for learning.
Notice that all students are attentive and look as if they are enjoying themselves. That's what happens when students come to Chemistry class and the teacher bursts forth with a humorous song about protons, neutrons and electrons.