Sundials

Sundials are the oldest time-telling instruments in history. Early versions of these time-telling instruments were seen as early as 1500 B.C.

How A Sundial Works

The basis of time telling time with a sundial involves the use of the position of the sun. As the sun shines onto a sundial, a shadow is cast. The position of this shadow is what is used to measure time.

In order to make telling time with a sundial easier, usually there are hour markers placed on the surface of it-much like the way numbers are displayed on a clock.

The Nature Of Sundial Time

Sundials tell what is called “apparent time”. What this means is that time is indicated by a sundial according to non-uniform movements of the sun over a period of time.

This is different than the time that is told by a clock, which measures “mean time”. Mean time is more uniform than apparent time measured by a sundial. (The difference between the mean time told by a clock and the apparent time measured by a sundial is called the “equation of time.”)

Types Of Sundial

One type of oldest types of sundials is the ancient “obelisk” timekeeper. This one was developed around approximately 3500 B.C. Even older than the obelisk-style timekeepers are the shadow clocks which were made in approximately 1500 B.C. (as mentioned in the beginning of this article).

Another type of sundial is the “equinoctial sundial”, which is considered to be one of the simplest types of sundials made. It consists of a disk mounted at an angle on a bar.

A similar type of dial is the “garden sundial.” This one is often also round, but the biggest difference is that it usually lies flat versus sitting up straight like the “equinoctial sundial.”

An alternative type of sundial is the “vertical sundial”. This one usually is painted on the side of a wall. A similar type of dial is called the “vertical direct” one which lines up with cardinal direction points, which are the same points used on a compass.

A large number of the types of sundials described above were made out of stone. However, others were made out of precious metals. The 18th century portable sundial was also made out of a semi-precious metal, usually brass.

Some of the newer models of sundials created are of an analog or digital model. Further information about these as well as the numerous other styles of both contemporary and ancient models of sundials can be easily researched online.

How To Make A Sundial

Making a sundial is an interesting project for a child or an adult. You have several methods that you can use for creating one of these timekeeping tools.

One method is to construct a horizontal sundial based on the approximate latitude location of where you live. For instance, you might possibly live in the North Hemisphere, at a position of 45° (degrees).

Another method for creating a horizontal sundial would be to combine your current latitude position plus the use of a protractor to create the correct angles. You can also use trygonomic equations if you are familiar with that mathematics method.

To start off with, you might consider trying your hand at making a miniature sundial. This one can be made with a variety of materials, such as a small wooden, clay Bristol board, or stone disk, along with nails, cord, and/or key ring.

You also may be successful at creating an accurate sundial with the use of modeling clay and cardboard. You will want to search online for the instructions on making various types of sundials- both vertical and horizontal.