The annual contest for students in grades four through 12 is back for its eighth year — this time with a special prize for a podcast that marks the 250th anniversary of the United States.

It's before school on a crisp Friday morning in Carlsbad, Calif. Andrew Luria is rallying the kids in his newsroom. "How many of you guys didn't do your homework?" Luria asks the 10- and 11-year-old ...