u/Intrepid-Truth8102

I teach year 7s and one class I have is a handful. Every lesson i'm always tell them to sit still and be quiet. Today i offered them that if they knuckled down for 40 min of the lesson, they can get free time for the rest of the lesson. I have never seen them so quiet and attentive. It was so weird. Is this a valid way of teaching or do you think this is bad in the long run?