Question

How many degrees apart are the 24 time zones? A) \(10^{\circ}\) C) \(15^{\circ}\) B) \(34^{\circ}\) D) \(25^{\circ}\)

Short answer

Each of the 24 time zones is 15° apart.

Step-by-step solution

Total Degrees in a Circle

A full circle is comprised of 360 degrees. This is the same for the Earth's longitude lines that divide the planet into time zones.

Count the Number of Time Zones

There are 24 time zones around the world. This is because the Earth completes one full rotation every 24 hours.

Calculate Degrees per Time Zone

To find how many degrees each time zone covers, divide the total degrees of the Earth by the number of time zones: \( \frac{360}{24} \).

Perform the Division

Divide 360 degrees by 24 time zones to find the degrees per time zone: \( \frac{360}{24} = 15 \).

Key concepts

Earth Rotation

The Earth's rotation is a fascinating process where the planet spins around its axis. This rotation is what creates the cycle of day and night. One complete rotation of the Earth takes approximately 24 hours. During this time, every point on Earth moves in a circular path around the planet's axis.

• **24-hour rotation:** The Earth rotates once every 24 hours, which is why a day is comprised of 24 hours.
• **Movement and time zones:** The rotation of the Earth causes different parts of the world to experience daylight and night at different times, leading to the creation of time zones.

The Earth's rotation is also responsible for the apparent movement of the sun across the sky. As the Earth rotates from west to east, the sun appears to move from east to west. This continuous movement influences the division of the Earth into 24 time zones, each one corresponding to one hour of Earth's daily journey.

Longitude Lines

Longitude lines, also known as meridians, are imaginary lines that run from the North Pole to the South Pole. These lines are crucial in defining time zones across the globe. Understanding their role gives clarity to how time zones are mapped out.

• **Vertical orientation:** Unlike latitude lines which are horizontal, longitude lines are vertical, extending from pole to pole.
• **Prime Meridian:** The zero-degree longitude line is known as the Prime Meridian, which runs through Greenwich, England, and serves as a starting point for measuring degrees east and west.

Longitude lines are spaced 15 degrees apart, connecting each time zone around the world. The division of Earth into these lines ensures a systematic way to calculate local time, as every 15-degree shift marks one hour of the Earth's rotation.

Degrees in a Circle

Degrees in a circle relate to the 360-degree measurement system used to divide circular shapes, like the Earth, into sections. Visualizing the Earth as a sphere with 360 degrees helps in understanding time zones.

• **Total degrees:** A complete circle, as well as the Earth, is divided into 360 degrees.
• **Division and time zones:** Since the Earth is a sphere, the 360-degree circle is utilized to divide the planet into 24 time zones, each 15 degrees apart.

This division comes from dividing the total degrees by the number of time zones: \( \frac{360}{24} = 15 \). Each time zone is separated by intervals of 15 degrees, facilitating a global time management system where each section correlates with an hour of the day.