[Zr40]

> With timezones:

> * I want to call my friend in Germany. What time is it for her? I guess I'm UTC-7 and she's UTC+1, so she's 8 hours ahead of me. I know that everybody around the world typically wakes up between 6 and 9 AM and goes to sleep between 8 PM and midnight, and she's an early bird, so she should be awake.

> Without timezones:

> * I want to call my friend in Germany. It's the same time here as there. It rises at 13:00 here, but she's a quarter of the way way around the world. I have to look up their typical waking hours. She's an early bird, so is she on the early side of that, likely. What time does the sun rise there? How much does that change over the seasons?

This is actually the same thing. In both cases you have to know or look up that there's an 8 hour difference between the two of you.

The bits about the seasons and being an early bird apply equally to both cases, so it's not really relevant to the comparison.

[watwut]

It is not the same thing. I do not need to reason at all right now, I just look at the clock that shows times in relevant timezones. I know all the information instantly, without any calculations in head at all.

In the latter case, you do need to do math, because what you are getting is meaningless number and then you need to convert it to some kind of "how long after typical start of day" format to get information you actually want.

[yencabulator]

Ah, so you're saying you have a clock showing German time, and it did the "math" for you.

Imagine multiple world clocks, in the typical Hollywood command bunker look. Instead of each clock having hour hands pointing in different directions, they'd all have the same hour hand position, but different highlighted zones for waking hours (or "shift 1", "shift 2", "shift 3", for 24h duty).