Changing the time of day is not as simple as just resetting the school clock, as folks at the Campbell County Board of Education are learning.

More than 100 parents showed up for a hearing Thursday on whether the district should flip-flop the starting times for its elementary schools and the middle and high schools.

Middle and high school students now begin the school day at 7:30 a.m. The bell rings for the elementary children an hour later. What prompts the discussion about reversing those times is some new research that indicates teenagers might do better with a later start time because puberty-related changes may make it difficult for them to fall asleep before 11 p.m. Using grade school arithmetic, it can be calculated that to get eight hours of sleep beginning at 11 p.m., you need to keep snoozing until 7 a.m.

But giving the older kids an extra hour before starting the day has repercussions that go far beyond the classroom. The basic living patterns of families have evolved around the established school day. Any alteration to that pattern causes pebble-in-the-pond disruptions that the school board has to consider.

Starting the elementaries an hour early means having six-year-olds out at the bus stops before the sun comes up. Because their days will then end an hour earlier, it means elementary children will be arriving home before the older brothers and sisters who working parents depend on for after school baby-sitting.

Any schedule change also will affect the families of 1,900 parochial school students who ride the same buses.

Then there is the question of the validity of the study. Is this 11 p.m.-7 a.m. adolescent sleep cycle a natural or a cultural phenomenon? Before the advent of electric lights and television, didn't most people get up at dawn and think about going to bed at dark?

None of this means that the time switch being considered in Campbell County isn't a good idea. It's just a reminder that every little change we make in our lives requires another adjustment, and another, and another, and another . . .

We urge the school board to take all this into consideration before making a final decision March 22. This change won't be as easy as clockwork.