Source: TH
Context: Throughout history, timekeeping has evolved from basic sundials and water clocks to advanced atomic and nuclear clocks.
| Period | Clock Type | Description |
| Ancient Times | Sundials, Water Clocks, Hourglasses | Used sunlight to cast shadows, and the flow of water or sand to measure time. |
| Middle Ages | Mechanical Clocks | Introduced the verge escapement mechanism, followed by spring-driven and pendulum clocks, enhancing accuracy. |
| 18th Century | Marine Chronometer | Invented by John Harrison, revolutionized navigation by providing precise timekeeping at sea for determining longitude. |
| 19th Century | Electric Clocks | Emerged using batteries or motors, moving away from purely mechanical components. |
| 20th Century | Quartz Clocks | Used quartz crystals oscillating at a fixed frequency for accurate time measurement. |
| Modern Times | Atomic Clocks | Use lasers to excite atoms, achieving extreme accuracy in time measurement. |
Current advancements include optical clocks, which use higher-frequency radiation for even greater precision, and researchers are working on nuclear clocks, which could potentially offer even higher accuracy by using the nuclei of atoms as resonators.
