I have not tested this on high schoolers, but it was magic in
I began every work session (whether it was at the beginning of class
or sometime in the middle) with mandatory quiet. I named it
"focusing time." The amount of time correlated to the grade (4th
grade = 4 minutes). I added an extra minute for each person who was
talking to anyone but me. I can't imagine needing more than 5 minutes.
What this did was allowed for students to get engrossed in the work
first. It also might help that you don't let them get loud first and
then try to reign them back in. Class starts calmly. Students that
have questions can ask me.
I hope that helps...someone! It's worked wonderfully for many of my
Dept. of Curriculum and Instruction
University of Maryland College Park