Por defecto: 

Lecture demonstrations have been an integral part of physics courses for more than a century, yet many instructors do not understand their importance or utilize this teaching tool effectively. Demonstrations do not replace laboratory experiments, but in a way, allow the entire class to collectively perform the experiment. When the students have a vested outcome in the end result, significant learning gains can be achieved. I will demonstrate these methodologies and share some of my favorite lecture demonstrations with you. Many of these, you can easily replicate at your institution