Time changes by one hour for each 15° degree change in longitude; this is because
A) it was determined by how fast 17ᵗʰ century ships could travel.
B) 15° insures that major population centers have unique time zones.
C) early navigation instruments did not allow better accuracy than 15 degrees.
D) 15° was chosen arbitrarily.
E) twenty-four latitude lines were chosen so that 24 hours represents a 360° revolution around the planet.

Question

Quizplus · Accepted Answer

The choice of 15° increments for time zones is based on the fact that the Earth rotates 360° in 24 hours, or 15° per hour. Therefore, twenty-four latitude lines were chosen so that 24 hours represents a 360° revolution around the planet, with each time zone encompassing 15° of longitude. This ensures that each time zone is roughly one hour ahead or behind the adjacent time zone.

Time Changes by One Hour for Each 15° Degree Change