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 time zone is 15 degrees apart.

Step-by-step solution

Understanding the Earth’s Circumference

The Earth's circumference is approximately 360 degrees, which represents a full circle around the globe. Time zones are determined based on the rotation of the Earth.

Determining the Division into Time Zones

The Earth is divided into 24 time zones. This is based on the rotation of the Earth which completes a full rotation (360 degrees) in 24 hours.

Calculation of Degrees Per Time Zone

To find how many degrees apart each time zone is, divide the total number of degrees (360) by the number of time zones (24). This calculation is done as follows: \[ \frac{360}{24} = 15 \]

Verifying the Result

The calculation shows that each time zone covers 15 degrees of longitude. This matches the standard practice for the distribution of time zones around the globe, confirming that each time zone extends 15 degrees apart.

Key concepts

Earth's Circumference

The Earth's circumference is a key factor in determining how we divide the world into time zones. Imagine wrapping a tape measure around the Earth along the equator; you would measure about 40,075 kilometers (24,901 miles). However, when we talk about the circumference in terms of degrees, we mean a 360-degree circle. This complete circle represents the surface of the Earth, with each degree helping us pinpoint locations precisely using lines of longitude.

The concept of the Earth's circumference is essential in understanding navigation and geography. Along with parallels of latitude, which are horizontal lines that circle the globe, degrees of longitude are vertical lines that run from the North Pole to the South Pole. These lines, when used with latitude, allow us to position any location on Earth. The 360 degrees are divided into segments to create time zones, which help us manage time effectively across the world.

Degrees of Longitude

Degrees of longitude are crucial in mapping out the Earth and are used to define time zones. Longitude lines are imaginary lines that run from the North Pole to the South Pole and are measured in degrees. The Prime Meridian, located in Greenwich, England, is at 0 degrees longitude, and it divides the Earth into the Eastern and Western Hemispheres. Each degree of longitude then extends up to 180 degrees east and west of the Prime Meridian.

For timekeeping, degrees of longitude are particularly important because they establish the time zones. The Earth is divided into 24 main time zones, based on its 360-degree rotation. This means every time zone ideally covers 15 degrees of longitude (\(\frac{360}{24} = 15\)). However, practical considerations like country borders and political convenience mean that real-world time zones don't always fit this ideal exactly, but the 15-degree guideline is a useful standard.

Earth's Rotation

Earth's rotation is the spin of our planet around its axis, and it is the fundamental reason why we have time zones. It takes about 24 hours for the Earth to make a complete 360-degree rotation, which is why there are 24 time zones. Each hour of the day's rotation is, therefore, equivalent to 15 degrees of longitude.

As the Earth rotates, different parts of the world move in and out of sunlight, creating the cycle of day and night. This rotation is from west to east, and as a result, time moves forward as we travel eastward. This is why when you fly east, you "gain" time, and when you fly west, you "lose" time.

• Earth completes one full rotation in 24 hours.
• This rotation is split into 24 time zones of equal duration.
• Each time zone ideally spans 15 degrees of longitude.

Understanding Earth's rotation helps us comprehend how time zones function, allowing for a synchronized global timekeeping system.