When I worked for Mad Science there was always like 6 ten to twenty minute activities. We had the kids for an hour. Include the time that I had to spend talking about the concept and explaining how to do the actives, that is way way more than needed. My trainer explained that he wanted to make certain that no matter what the class, there was some activity that everyone could enjoy. It was my job as a teacher and part of classroom management to chose activities on the fly that would fit the group.
Planning for a dance class I’ve adopted this method. In my planning stages, there’s a dozen things that I think should be said for each of the handful of exercises or movements I choose to cover. I never get to to do all of the movements, and not all of the things that could be said should be said to the group that is in front of me. At that moment in my life I was learning so much about learning and teaching both on the job and in classrooms. I’ve carried that forward, and I feel lucky that I’ve had these opportunities.