Is it AM or PM?

Second-graders have been learning to tell time using a.m. and p.m.!  In Ms. Dekker's class students were shown a picture of an event.  Using the clues in the picture (what are the people doing, how much light is outside), students wrote a time on their whiteboard that made sense.  When Ms. Dekker said, "Show me" students walked to the left or right side of the room to show if their answer was a.m. or p.m..  Sometimes students all agreed and other times they had different answers that were still correct.  For example, they all agreed that New Year's Day starts at 12:00 a.m., but lunchtime could be 11:50 a.m. or 12:00 p.m.!