Taking a brain break at 20-25 minutes intervals in our classes has three benefits:
1. we get a short rest from our teaching and the kids can get out of their restraining devices for a moment or two and relax.
2. tossing a ball, etc. drops the just learned material from the desktop into the hard drive, from short term into long term memory, as per all the crucial research of the past years discussed in books like Brain Rules, etc.
3. perhaps most importantly, we can get to know some of our quieter kids with whom we have little or no connection. Many of us go through the entire year without even talking with certain kids, favoring others. I maintain that it is not possible to teach a kid anything without first having had some kind of meaningful conversation with him or her. How can a child be interested in what you are about if you are not interested in what they are about?