Globe/T. Rob Brown
Kevin Cochran, 17, of Lafayette, Calif., tries to keep his balance on a large, inflatable ball at Schifferdecker Park Pool Thursday afternoon, Aug. 2, 2012. Cochran and fellow youth group tornado cleanup volunteers from the Oakland, Calif., included 52 students and 12 advisers who needed to cool off after working in the heat all day.

T. RobBrownJoplinMissouriMOSchifferdecker ParkSchifferdecker Poolpoolballinflatable ballKevinCochranKevin CochranLafayetteCaliforniaCalifCAOakland