The sundial is one of the world’s oldest known devices for measuring time, dating back thousands of years to ancient Babylon. Garden sundial uses today include sundial garden accessories, and you can easily make your own.

Sundial History: From the Sundial Stick to the Sundial

Before we had clocks and watches, people used the Sun to tell time. The sundial was a popular method of using the Sun to tell time for thousands of years, from about 2,000 BC to 1,400 AD.

The ancestor of the sundial was the sundial stick, which was probably used in prehistoric times to track the Sun’s seasonal movements. The sundial stick was based on the same observations and theory of time measurement that would later inspire the sundial.

Early observers noticed that after breaking the horizon at dawn, the Sun rises in the sky until it reaches its peak at noon, and then it descends to the horizon again at dusk.

They also noticed that while this is happening, the Sun’s shadow starts out long at dawn, grows short at noon, and again grows long at dusk. This is because when the Sun is low, the whole side of the stick is being hit by the Sun and casting a shadow; but when the Sun is high, the Sun is more angled towards the top of the stick, shortening the amount of the stick casting the shadow.

Meanwhile, the Sun’s shadow falls at different angles at dawn, noon, and dusk. At dawn, the Sun is hitting the stick from the east and casting a shadow angled partway towards the west. By dusk, this is reversed. Meanwhile at noon, the Sun is casting a shadow halfway between east and west, angled straight up and down.

Because of this, by putting a “sundial stick” in the ground and noticing how long the Sun’s shadow is and where it falls, it is possible to estimate the time.

Early observers further noticed that the peak of the Sun at noon is lowest in the sky in winter and highest in summer. During the summer months, the Sun is more directly overhead than in winter. This further affects the length and angle of the Sun’s shadow.

Due to this, by putting a sundial stick in the ground and marking where the Sun’s shadow falls at noon on different days of the year, it is possible to draw an arc on the ground that graphically symbolizes the Sun’s annual path. Some researchers believe that this method was used to lay out the circles at Stonehenge, which is currently dated between about 2,200 and 3,100 BC.

At about the same time, around 2,000 BC, the Babylonians are believed to have already been using the sundial, which was essentially a refinement of the sundial stick. The first written reference to the sundial comes from the Babylonian priest Berossus, who wrote in the 3rd century BC. Berossus described a sundial that was a hollow dome set with its edge flat and a small bead fixed at the center. Over the course of the day, the shadow of the bead moved in a circular arc, dividing the day into 12 equal parts. These were called temporary hours, because their length varied with the seasons. This concept of temporary hours became the basis of equal hours when clocks were invented around 1400 AD. In this way, the Babylonian sundial became the ancestor of today’s time-keeping methods.

How a Sundial Works

A sundial consists of two parts:

1. A plane, also called a dial face or dial plate.
2. A gnomon.

The dial face is a flat circle divided into hours, sometimes with half hour and quarter hour divisions added. Many sundials have faces painted in Roman numerals from 5 am to 8 pm.

The gnomon is a flat piece set in the center of the dial. It is usually made of metal, replacing the wooden sundial stick. It may have an edge called a style and a pointed tip called a nodus.

The gnomon points to true North for sundials in the Northern Hemisphere and true South for sundials in the Southern Hemisphere. The upper edge of the gnomon must slant upward from the dial face at an angle equal to the latitude of the location of the sundial. This is to take into account how latitude affects the angle of the Sun in the sky.

When the sun hits the gnomon, it casts a shadow. Where the shadow falls tells the time.

How to Make Your Own Sundial

You can make your own sundial using three simple items:

1. A straight stick or pole
2. Some stones or similar objects you can place on the ground to mark hours
3. A clock or watch to synchronize your sundial

Make Your Own Wooden Sundial

To make your sundial, follow these steps:

1. Erect your stick somewhere in your yard that gets sun most of the day. You can stick it in the ground or in a support base such as a bucket of dirt, as if you were planting a tree.
2. Every hour, place a stone to mark where your stick’s shadow falls.
3. After you have marked off a complete set of hours (which may take you a couple days if you started late in the day), you will have a complete sundial.

You can now use your sundial to tell time without a watch!

Worthy Video: Human Sundial

Related Posts

No related posts found