Solar Clocks
 Bead Panel, Bahau people. Borneo 20th century, diameter 18 cm. From the Teo Family collection, Kuching. Photograph by D Dunlop.

Any clock that depends on observing the brightness or darkness of visual sensations from the Sun is called a solar clock. The most basic solar clock is just squinting at the Sun. But historically, extremely elaborate and complex sundials have been widely used as solar clocks as well. By the foregoing definition all solar clocks are at least partly objectified from black and white sensations. So any solar clock may be characterized by a count of its up-seeds $N^{\sf{U}}$ and down-seeds $N^{\sf{D}}$. These numbers determine a clock's spin which can then be used to establish the phase of any other particle P as

$\delta _{\theta} ^{\, \sf{P}} = \begin{cases} +1 &\text{ if } \ \ \ N^{\sf{U}} > N^{\sf{D}} \\ \ \, 0 &\text{ if } \ \ \ N^{\sf{U}} = N^{\sf{D}} \\ -1 &\text{ if } \ \ \ N^{\sf{U}} < N^{\sf{D}} \end{cases}$

When this phase is used to make relative descriptions of terrestrial events, it can be interpreted as $\delta _{\theta} = +1$ if an event occurs during the day, or $\delta _{\theta} = -1$ if an event occurs at night. Solar clocks are always available to provide this semantic anchor for interpreting the phase because seeing the Sun is assumed to be a reference sensation for WikiMechanics. One cycle of a solar clock may be called; a solar day, or twenty-four hours, or a circadian cycle, or a nychthemeron, or usually we just call it a day. For more detail, see the articles in the menu below that are marked with this icon

 Next step: other clocks.

Related WikiMechanics articles.

 Summary
 Noun Definition Solar Clock A clock that depends on visual sensations from the Sun. 6-10
 Noun Definition Day One cycle of a solar clock. 6-11
page revision: 116, last edited: 11 Dec 2017 21:29