On a recent morning at Visitacion Valley Middle School in South San Francisco, Principal James Dierke looked out over the school’s auditorium at more than 100 eighth graders. A restless din filled the large room. Bursts of laughter and errant shouts punctuated the buzz. Most of the students seemed disinterested in Dierke’s announcements about the spring’s impending graduation, upcoming field trips, and recent birthdays.
Then, Dierke struck a bell and said, “Okay, it’s quiet time.”
And just like that, a hush fell over the auditorium. Students straightened their backs and closed their eyes. Some bowed their heads. Others rested them on the backs of …
