Clocks

                 Evolution of time Measurement    

Sundial: 

                    A triangular blade called gnomon is fixed vertically over horizontal dial marked with hours of the day, and placed in the open. as the sun progresses in the sky, the position and the length of the shadow of the gnomon on the dial changes, giving the measurement of  time.

Sand Glass:

                  A definite amount of sand is allowed to slowly flow down from the upper to the lower glass is also called an hour glass. Once emptied, the sand glass is turned upside down to record the time again.

Candle clock:

                 This was primarily use d when a sundial  could not be used for example on cloudy days or in the night.

Water clock:

                   Water is allowed to drip down from one container to another placed under it. Every time, it takes the same amount of time for the water to drip from the upper to the lower container

water clock

Sundial

Candle clock

Sand clock