Time zones help keep social life across the world consistent but they can have different effects on social life within each time zone:

Now, Google engineer Stefano Maggiolo has visualized what this difference looks like around the world—how solar time lags behind or marches in front of the time on the clock. It’s a rare look at the rhythm of the day—measured and made uniform by technology—affects communities around the world…

Of course, the reasons for standardization are often as sociological as they are technological—and their effects wind up redounding beyond their intent. As Joshua Keating writes at Slate, Spain standardized on central European time during Franco’s reign. This, in turn, led to later schedules in Spain, and to the nation’s famously nocturnal suppers.

“At the time I’m writing, near the winter solstice, Madrid’s sunset is around 17:55, more than an hour later than the sunset in, for example, Naples, which is at a similar latitude,” writes Maggiolo.

It was Spain’s extreme offset that led to Maggiolo’s writing the story.

China, too, uses a single time zone across its territory, which works for the country’s more urban east but hurts the country’s rural west. India does the same—to, as it happens, the opposite effect. In India’s easternmost state, the summer sun can rise as early as 4:30 a.m.

Some historians argue that the invention of the clock and the subsequent development of clock time had a profound effect on civilization. But, tweaking time zones, whether countries want to have a single zone or want to be half an hour off or areas don’t want to switch for Daylight Savings Time (we experienced this in northwestern Indiana so half the year we were on eastern time, half on central time), can lead to some different outcomes and social patterns. In these instances, time can serve nationalistic (in the case of having a single time zone for one country) or economic (the northwest corner of Indiana is on central time and not eastern time like the rest of the state to maintain its ties to Chicago) purposes.

This makes me think that it would be pretty interesting to study people and communities right at the edges of these zones. If India and China have different single time zones, what happens at their border where there is a substantial 2.5 hour difference? Even consistently traversing a one hour time different in the U.S. within one metropolitan area could be interesting.