Frances Tal1ey, age 10, of Springfield, Ore., for her question:

At noon in Oregon, what is the time in Vietnam?

The round globe is divided into 24 time zones. Each zone runs from pole to pole like an orange section. In Each calendar day, the time moves hour by hour from east to west through the 24 zones. The calendar day begins at the international date line in the time zone that runs down the mid Pacific. The new calendar day creeps westward hour by hour, zone by zone.

After four hours, the new day dawns in Vietnam. After 20 hours it reaches Portland, oregon. The same day Ends at the date line and the next calendar day creeps westward through Vietnam. And much later through oregon. Saigon is only Eight time zones westward from Portland, but the two points are separated by the date line. When the clocks of Portland strike noon on Tuesday, it will be Wednesday morning and 4 a.m. in Vietnam.