Understanding Earth's Time Zones

The Earth completes a full rotation of 360 degrees in 24 hours. Time zones are established to standardize time across different geographical regions, primarily based on the Sun's position. Since there are 24 hours in a day and the Earth rotates 360 degrees, we can calculate the longitudinal extent of each time zone.

Calculating Longitudinal Extent

To determine how much longitude corresponds to one hour, we divide the total degrees of rotation by the total hours in a day.

• Total degrees in a full circle (Earth's rotation): $360^\circ$
• Total hours in a day: 24 hours

The calculation is as follows:

$$ \text{Longitudinal Extent per Hour} = \frac{\text{Total Degrees}}{\text{Total Hours}} $$

Substituting the values:

$$ \text{Longitudinal Extent per Hour} = \frac{360^\circ}{24 \text{ hours}} $$

Performing the division:

$$ \frac{360}{24} = 15 $$

Therefore, one hour of time difference corresponds to a longitudinal extent of $15^\circ$.

Time Zone Coverage

Based on this calculation, Earth is divided into 24 standard time zones, each ideally covering approximately $15^\circ$ of longitude. This system helps in synchronizing local times with the apparent position of the sun, although political and geographical boundaries often cause deviations from these standard lines.

The question asks for the longitudinal extent covered by one time zone of one hour each. As calculated, this extent is $15^\circ$.