I was preparing for my first year classes and reread this “original” article from physicist Carl Weiman that was published in 2005 in Physics Today.

http://scitation.aip.org/content/aip/magazine/physicstoday/article/58/11/10.1063/1.2155756

Ten years later, I felt that it is still relevant and I have shared that with the TAs of this class.

Active learning strategies can be implemented in different scales.  It can be just one class out of the entire term, to every class, 5 minutes to 50 minutes of class time.  I hope this helps give some insights to improve our teaching.

Eugene