Why are the time zones calculated as 360°/24 and not 361°/24 or 360°/23.933? Background: I'm training to be a geography teacher. Currently I have practice lessons and I'll be discussing solar time and standard time with the class. Now I stumbled over an issue to which I could not find an answer:
We teach the students:

Sidereal day: In 23 h 56 min the earth rotates 360°
Solar day: In 24 h the earth rotates 361°

We also teach that in order to construct time zones (as a replacement of solar time), one divided 360° by 24 (to have a zone for each hour of the day), which results in 24 zones with 15° each.
Now my question is: Why does one mix the measures for sidereal day and solar day? Or put differently: Why doesn't one calculate 361°/24 or 360° / 23.933?
The Earth takes 23 hours 56 minutes to rotate once.  But that is not relevant to most people. Sure, the stars will be in the same position again after 23 hours 56 minutes, but the sun will not be in the same position.
It is far more important, for most people, to measure the time from noon to noon. And the average time from noon to noon is 24 hours. This is because the motion of the sun is a combination of both the spinning of the Earth and the orbit of the Earth around the sun. The orbital motion of the Earth adds four minutes. You should also teach the students

In twenty-four hours the sun advances 360 degrees. (solar day)

Time zones are based on clock time, which is based on the motion of the sun and not the motion of the stars.