Sandy and Cindy Wulff, age 15, of Parma Heights, Ohio, for their question:

 Will We gain or lose a day at the Date Line?

These pen pals are going on an orchestral tour to the Philippines, Japan and who knows where. Naturally their global travels will take them across the International Date Line that zig zags down the mid Pacific. What happens there depends upon whether they approach the famous line from the east or the west. Most likely they will depart from the coast of California and travel westward across the Pacific. In this case, they will skip a day at the Date Line. If they recross the Pacific on their return journey, they will be traveling eastward. This time they will have an extra day when they cross the Date Line.

Time marches westward, hour by hour around the globe. Each new calendar day begins at the Date Line that marches, more or less, along Longitude 180 degrees that runs from pole to pole down the mid Pacific. For example, if it is Sunday on the east side of the line then it is Monday on the west side. If you cross going west, you jump ahead and lose a calendar day. If you cross going east, the calendar backs up and you gain a day.