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: ...