Why do we need time?

Answer 1

Since the Earth is spherical, at any given time the sun will appear in different parts of the sky from different locations, and for half of the planet, it will be night. So, when it is morning on one side of the world, it is evening on the other. Before the invention of clocks, we approximated time by the position of the sun. Later, when clocks were common, each town set its own time. This worked relatively well until trains became a common form of transportation. Since each town followed its own time setting, train schedules were very confusing and disorganized, so we created a standard set of time zones to make coordinate the trains. Time zones have become even more essential since airplanes and telecommunications have emerged.