Why Do We Have ‘Time Zones’ and How Did They Start?

Imagine the whole world uses just one clock, everyone eats lunch at the same time, even if it's still dark in some places. That would be silly! So people started dividing the Earth into time zones, like slices of a pie, so each place has its own time that matches when the sun rises and sets. This idea began with the invention of trains, they needed to know what time it was in different cities to run on schedule.

Each time zone is about 15 degrees around the Earth, which makes sense because the Earth rotates 360 degrees every 24 hours. That means each hour of time difference corresponds to a 15-degree shift across the globe.