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| title | chunk | source | category | tags | date_saved | instance |
|---|---|---|---|---|---|---|
| Chronometry | 2/3 | https://en.wikipedia.org/wiki/Chronometry | reference | science, encyclopedia | 2026-05-05T14:27:50.668059+00:00 | kb-cron |
=== Mental chronometry === Mental chronometry (also called cognitive chronometry) studies human information processing mechanisms, namely reaction time and perception. As well as a field of chronometry, it also forms a part of cognitive psychology and its contemporary human information processing approach. Research comprises applications of the chronometric paradigms – many of which are related to classical reaction time paradigms from psychophysiology – through measuring reaction times of subjects with varied methods, and contribute to studies in cognition and action. Reaction time models and the process of expressing the temporostructural organisation of human processing mechanisms have an innate computational essence to them. It has been argued that because of this, conceptual frameworks of cognitive psychology cannot be integrated in their typical fashions. One common method is the use of event-related potentials (ERPs) in stimulus-response experiments. These are fluctuations of generated transient voltages in neural tissues that occur in response to a stimulus event either immediately before or after. This testing emphasises the mental events' time-course and nature and assists in determining the structural functions in human information processing.
=== Geochronometry === The dating of geological materials makes up the field of geochronometry, and falls within areas of geochronology and stratigraphy, while differing itself from chronostratigraphy. The geochronometric scale is periodic, its units working in powers of 1000, and is based in units of duration, contrasting with the chronostratigraphic scale. The distinctions between the two scales have caused some confusion – even among academic communities. Geochronometry deals with calculating a precise date of rock sediments and other geological events, giving an idea as to what the history of various areas is, for example, volcanic and magmatic movements and occurrences can be easily recognised, as well as marine deposits, which can be indicators for marine events and even global environmental changes. This dating can be done in a number of ways. All dependable methods – barring the exceptions of thermoluminescence, radioluminescence and ESR (electron spin resonance) dating – are based in radioactive decay, focusing on the degradation of the radioactive parent nuclide and the corresponding daughter product's growth.
By measuring the daughter isotopes in a specific sample its age can be calculated. The preserved conformity of parent and daughter nuclides provides the basis for the radioactive dating of geochronometry, applying the Rutherford Soddy Law of Radioactivity, specifically using the concept of radioactive transformation in the growth of the daughter nuclide. Thermoluminescence is an extremely useful concept to apply, being used in a diverse amount of areas in science, dating using thermoluminescence is a cheap and convenient method for geochronometry. Thermoluminescence is the production of light from a heated insulator and semi-conductor, it is occasionally confused with incandescent light emissions of a material, a different process despite the many similarities. However, this only occurs if the material has had previous exposure to and absorption of energy from radiation. Importantly, the light emissions of thermoluminescence cannot be repeated. The entire process, from the material's exposure to radiation would have to be repeated to generate another thermoluminescence emission. The age of a material can be determined by measuring the amount of light given off during the heating process, by means of a phototube, as the emission is proportional to the dose of radiation the material absorbed.
== Time metrology == Time metrology or time and frequency metrology is the application of metrology for timekeeping, including frequency stability. Its main tasks are the realization of the second as the SI unit of measurement for time and the establishment of time standards and frequency standards as well as their dissemination.
== History ==
Early humans would have used their basic senses to perceive the time of day, and relied on their biological sense of time to discern the seasons in order to act accordingly. Their physiological and behavioural seasonal cycles mainly being influenced by a melatonin based photoperiod time measurement biological system – which measures the change in daylight within the annual cycle, giving a sense of the time in the year – and their circannual rhythms, providing an anticipation of environmental events months beforehand to increase chances of survival. There is debate over when the earliest use of lunar calendars was, and over whether some findings constituted as a lunar calendar. Most related findings and materials from the palaeolithic era are fashioned from bones and stone, with various markings from tools. These markings are thought to not have been the result of marks to represent the lunar cycles but non-notational and irregular engravings, a pattern of latter subsidiary marks that disregard the previous design is indicative of the markings being the use of motifs and ritual marking instead. However, as humans' focus turned to farming the importance and reliance on understanding the rhythms and cycle of the seasons grew, and the unreliability of lunar phases became problematic. An early human accustomed to the phases of the moon would use them as a rule of thumb, and the potential for weather to interfere with reading the cycle further degraded the reliability. The length of a moon is on average less than our current month, not acting as a dependable alternate, so as years progress the room of error between would grow until some other indicator would give indication.