Here is a picture of two travellers on the island of Tavenui in Fiji where the international date line crosses one of the islands. They had to draw the international date line around the Fijian islands otherwise half the island would be living in yesterday and the other half would be living in today. This would make getting to exams on time very complicated for pupils on the island who lived on different sides of the date line.
If it is 11am for the travellers in Fiji what time is it for everyone back in Dartford? You need to think about how many hours there are in a day and also how many degrees the earth turns through. It also helps greatly to know that Greenwich in England is on the 0º line of longitude and the international date line is on 180º.
In the picture one of the travellers is standing in today and one is standing in yesterday. They only have to take one step to travel back or forward in time. How does that work?
Learning is like travelling, you find out a lot of stuff along the way, but you keep on bumping into new questions that need answers.
(Written by my brother Michael Drury - Thank you!)