Students at Tulip Grove Elementary may not know the price tag for true peace at school.

But they're working toward that goal, one penny at a time.

Since the middle of February, students in each of the school's 12 classrooms have been putting their loose change in watering cans located in their homeroom. For each penny donation, students receive a green leaf on which they write messages of peace. The leaf is then added to a paper tree located in the lobby at the school entrance.

"We've been counting our days of peace during the whole school year, which has been almost every single day, and it's really amazing," Principal...