For a free trial of World Book Online, click here. Time is one of the world's deepest mysteries. No one can say exactly what it is. Yet, the ability to measure time makes our way of life possible.
Most human activities involve groups of people acting together in the same place at the same time.
People could not do this if they did not all measure time in the same way. One way of thinking about time is to imagine a world without time. This timeless world would be at a standstill. Thus, time and change are related because the passing of time depends on changes taking place. In the real world, changes never stop happening.