## Find a Sundial

Find a Sundial and... Show It To Us!

Since Man became aware about the periodic character of the day, the attempts to measure time have been systematic. Using the beat of the heart and by developing simple instruments, Man started to try to measure time.

At a certain point our human ancestors guessed the time of day by observing the sun's movement from morning until night. Sunrise and sunset required no calculation, mid day (or noon) was a little bit trickier, but the time between these three reference moments left them baffled.

Their observations showed them that shadows cast changed in length and moved throughout the day. After a while they understood that it would be easier to measure the passing of time by observing the change in shadow lengths than by observing the movement of the Sun directly. This was the birth of Sundials.

During History, sundials have evolved into many forms and are widely spread out European countries.

So we challenge you: Find a Sundial... and tell us about it.

We propose in this page a simple competition for all students in Europe.

In many European towns and cities, walking the streets, we find sundials of various shapes and sizes. Some are old and they were built to be used as a way of measuring time. In many cases the only one available. Others, more modern, are built in prominent places as pure ornament and we can also find sundials in private houses and gardens.

Time “keeping” is simply a matter of counting cycles or units of time. A clock is what does the counting. In a more strict definition, a clock also keeps track of its count and displays what it has counted. In a broad sense, the Earth and the Sun are a clock -the commonest and most ancient clock we have, and the basis of all other clocks.

A sundial is in essence simply any form of stick - known as a style or gnomon - which casts a shadow. The position of the shadow can then be used to determine the current solar time.

Sundials indicate the local solar time, unless otherwise corrected. To obtain the standard clock time, three types of corrections need to be made.

Babylonians and Egyptians built obelisks which moving shadows formed a kind of sundial, enabling citizens to divide the day in two parts by indicating noon.

To participate you have to make a previous registration. You have to fill up the registration form and send it to us.