Samuel Chiltern answered
The sundial is an ancient invention, and for this reason, nobody can be 100% sure who invented it.
The Earliest Sundials
The first sundials would have been no more than sticks pushed into the ground.
The direction and length of the shadow cast by the sun would have helped the person using the stick 'sundial' to estimate the time of day.
A person might have even known how to estimate the length of their own shadow in order to tell the time.
There is no way of knowing when this technique was developed, since the actual instruments themselves wouldn't have been preserved though time. It's also doubtful that these early users would have written anything down to document what they had invented.
However, there is some evidence, from ancient archaeological records belonging to the ancient Egyptians and Babylonians, and this stretches back as far as 5,500 years.
The ancient Greeks then went on to refine the principles of the sundial in approximately 560 BC, and the Romans later adopted their ideas.
How Sundials Work
Shadow-casting sundials work by using something called a gnomon to throw a shadow on to a surface which has markings on it to indicate the time of day. The gnomon must have a straight edge, but it can be orientated horizontally, vertically or in alignment with the Earth's axis.
Sundials can be very tricky to set up: It's usually necessary to know the local latitude and the direction to true North. Even then, a sundial will indicate solar time, rather than clock time, unless further adjustments are made. This makes them very poor timekeeping devices for the modern world, so they are often used as decorative features instead.
The Earliest Sundials
The first sundials would have been no more than sticks pushed into the ground.
The direction and length of the shadow cast by the sun would have helped the person using the stick 'sundial' to estimate the time of day.
A person might have even known how to estimate the length of their own shadow in order to tell the time.
There is no way of knowing when this technique was developed, since the actual instruments themselves wouldn't have been preserved though time. It's also doubtful that these early users would have written anything down to document what they had invented.
However, there is some evidence, from ancient archaeological records belonging to the ancient Egyptians and Babylonians, and this stretches back as far as 5,500 years.
The ancient Greeks then went on to refine the principles of the sundial in approximately 560 BC, and the Romans later adopted their ideas.
How Sundials Work
Shadow-casting sundials work by using something called a gnomon to throw a shadow on to a surface which has markings on it to indicate the time of day. The gnomon must have a straight edge, but it can be orientated horizontally, vertically or in alignment with the Earth's axis.
Sundials can be very tricky to set up: It's usually necessary to know the local latitude and the direction to true North. Even then, a sundial will indicate solar time, rather than clock time, unless further adjustments are made. This makes them very poor timekeeping devices for the modern world, so they are often used as decorative features instead.
