clocks, watches and sundials

Chapel Hill Sundial Carmichael

The development of the mechanical clock redefined our sense of time.



Clock – an instrument for measuring, indicating and maintaining the time. In general usage today, however, a “clock” refers to any device for measuring and displaying the time. But more specifically

  • clock – a device with a striking mechanism for announcing intervals of time acoustically, by ringing a bell, a set of chimes, or a gong.
  • timepiece – a silent instrument lacking an acoustical mechanism
  • watch – worn on the person.



Hourglass, Sandglass, Sand Timer, Sand Watch, Sand Clock, Egg Timer – measures the passage of a few minutes or an hour of time. It has two connected vertical glass bulbs allowing a regulated trickle of material from the top to the bottom. Once the top bulb is empty, it can be inverted to begin timing again. The name hourglass comes from historically common hour timing. Factors affecting the time measured include the amount of sand, the bulb size, the neck width, and the sand quality. Alternatives to sand are powdered eggshell and powdered marble. In modern times, hourglasses are ornamental, or used when an approximate measure suffices, as in egg timers for cooking or for board games.

Egg timer (mechanical)


Learn more…

  • Bill Nye – Telling time – At Solar Noon, when the Sun culminates, that is, reaches its highest point in the sky, the sun-shaped feature will light up. It is the marrying of mechanical and electrical engineering with astronomy.
  • Clocks – vocabulary list