Sharon Lurye and Jocelyn Gecker (The Associated Press), Lily Altavena (Chalkbeat), and Ruth Serven Smith (AL.com)

MODESTO, Calif. – Before every important test, teacher Nancy Barajas dims the lights, turns on a disco ball and blasts music from her playlist. Her sixth graders dance together as a “pre-celebration” to boost their confidence, then take their exam. Lately...