In ancient times, people measured time by natural phenomena. Over time some devices were invented for measuring time.
Some of them are given below:
(1) Solar Clock. A change in the position of the sun due to a change in the position of the shadow is used to measure time.
(2) Hour Glass. To measure the time it takes one hour for sand to flow from one bulb to another.
(3) Water Clock. Used to measure the flow of water from one vessel to another at a particular time.
(4) Pendulum. A simple pendulum takes equal time for each oscillation. So Pendulum was used to measure time.