Changing Times: The Confusing World of Time Zones
In the small US town of College Corner, there was a time when it was possible to throw a basketball from one side of the school court at 1 p.m. and for the ball to fall into the net at 2 p.m.
The town is on the border of the states of Ohio and Indiana, and the border goes right through the middle of the school's basketball court.
Until 2006, for a large part of the year, there was a one-hour difference between the two sides of the town — Ohio was in one time zone and Indiana was in another.
It could sometimes make it a little difficult to make plans!
Now, the town is all in the same time zone, but it's an example of the interesting way that the world's time zones can work.
There are 38 different time zones in use around the world, though some are just half an hour off their neighbors.
These time zones are measured from the Prime Meridian, the line of 0 degrees longitude that passes through Greenwich in London. Travel east from there and you're getting further ahead, travel west and you're going back in time.
But of course, the world doesn't always fit into straight lines, for political and geographical reasons.
And, as the residents of College Corner knew, time zones can be impractical.
That's why China chooses to have just one time zone, even though the country is about as wide as the US mainland, which has four.
This means that the sun's position in the sky doesn't match the time in some parts of China. For example, in the west of the country, the sun sometimes rises at 10 a.m.!
Map showing time zones around the world.
