Locating Places on Earth Notes

Models and Representations of the Earth

A globe is defined as a small model of the Earth, providing a three-dimensional representation of the planet's spherical shape. While globes offer a high degree of accuracy regarding the relative sizes and shapes of continents and oceans, maps serve a different practical purpose. A map is a drawing of the entirety of the Earth or a specific part of it rendered onto a flat surface. The primary utility of maps is that they help individuals locate places easily, offering a portable and detailed alternative to a three-dimensional globe.

Understanding Latitudes and Longitudes

The Earth is covered by an imaginary grid system consisting of latitudes and longitudes. Latitudes are lines that run from the east to the west across the globe. Although they run horizontally, a latitude tells the specific north or south position of a location relative to the Equator. Conversely, longitudes are lines that run from the north to the south, extending from pole to pole. A longitude tells the specific east or west position of a location. A key reference point in this longitudinal system is the Prime Meridian, which is established at $0^{\circ}$ longitude.

The Measurement of Time and Earth's Rotation

The Earth's rotation on its axis is the fundamental basis for our measurement of time. The Earth takes exactly $24$ hours to complete one full rotation. Because the Earth is a sphere representing $360^{\circ}$ in total, it is divided into $24$ time zones to correspond with the duration of its rotation. Each of these time zones covers approximately $15^{\circ}$ of longitude, calculated by dividing the $360^{\circ}$ of the Earth's circumference by the $24$ hours in a day. As a result of this organization, different places across the world have different local times depending on their longitudinal position.