Whole class reward system for a middle school science teacher. Create a positive competition between your classes and see which is the best behaved. When the whole class is showing respect and following directions (or just being totally awesome) add a marble to the jar. The class that fills the jar first wins a reward of your choosing. Maybe a fun lab just for them, or a snack on friday?!
Doc comes with 5 jar labels and a list of ways to fill the jar. You can edit jar labels to fit your class needs.