What is a sundial, and how does it work?

rahim10

A sundial is a device that uses the position of the sun to tell time. It is one of the oldest and simplest ways to tell time.


A sundial consists of a flat surface, called the dial, and a gnomon, which is a rod or other object that casts a shadow on the dial. The gnomon is typically aligned so that it points to the North Pole.

As the sun moves across the sky, the shadow of the gnomon moves Shadow and Reflection across the dial. The position of the shadow on the dial indicates the time of day.

The earliest sundials were probably just sticks that were placed in the ground. As the sun moved across the sky, the shadow of the stick would move, indicating the time of day.

Later, sundials became more sophisticated. They were made with flat surfaces and gnomons that were carefully aligned. Sundials were often decorated with intricate designs.

Sundials are still used today in some parts of the world. They are also popular among collectors.

Here are some of the different types of sundials:

Equatorial sundial: An equatorial sundial is a sundial that is aligned with the equator. This means that the gnomon is perpendicular to the Earth's axis of rotation. Equatorial sundials are the most accurate type of sundial.

Equatorial sundialOpens in a new window
www.researchgate.net
Equatorial sundial

Horizontal sundial: A horizontal sundial is a sundial that is aligned with the horizon. This means that the gnomon is parallel to the Earth's surface. Horizontal sundials are the most common type of sundial.

Horizontal sundialOpens in a new window
www.helios-sonnenuhren.de



Horizontal sundial
Vertical sundial: A vertical sundial is a sundial that is aligned with the vertical axis of the Earth. This means that the gnomon is perpendicular to the Earth's surface and points directly upwards. Vertical sundials are not as accurate as equatorial or horizontal sundials, but they can be used in places where the horizon is not visible.
Vertical sundialOpens in a new window

www.merlinsundials.co.uk
Vertical sundial

Sundials are a fascinating way to learn about the sun and how it moves across the sky. They are also a reminder of the ingenuity of our ancestors, who figured out how to use the sun to tell time long before the invention of clocks and watches.