The sundial is a clock that indicates the time according to the projection of sunlight, that is, it is a device that does not depend on mechanical work.
The need to measure time encouraged the invention of ways that served so that people could orient themselves in time. This was important for them to know, for example, what the planting and harvesting times were.
One of these first forms of mediation is the sundial, invented many years ago. After him came the water clock and sand clock, which are also known respectively by the names clepsydra and hourglass.
The obelisks, true architectural works, are the oldest sundials in the world. Built in Ancient Egypt, the oldest dates from 3500 BC. C approximately.
The simplest sundials are those whose dial is a flat surface. There are clocks with slanted dials.
Even today we can find this type of antique clock in gardens, providing more beauty to these public spaces.
How it works?
Watch faces are divided by lines, which correspond to the hours. They have a vertically fitted rod, which is a kind of pointer. It's called a gnomon and it's he who casts a shadow as the sun moves.
The shadow indicates the time. It should be noted that the sundial is not as accurate as a conventional watch. That's because it doesn't have minute scales, so it only measures hours.
In order for it to work properly, it is very important that your rod is aligned with the Earth's axis of rotation.
Also, it is important to remember that, since it is a sundial, its function can only be checked on a sunny day.
Read too:
- Time zones
- How to Turn Minutes into Hours
- rotation movement
- Time Measurements
