Customary units of measure such as the foot and the pound are suitable for everyday purposes such as measuring the dimensions of a person or a room. Metric (SI) units of measure such as the Kelvin and the kilogram are suitable for scientific purposes. Some metric units are suitable for everyday use, and they are so used in many countries.
However, there are some draw-backs to metric units for everyday purposes, for example: the SI unit of temperature is the kelvin (K) which does not relate to the temperatures of everyday life (even the related degrees Celsius compresses surface air temperatures into a narrow band); the kilometre is rather short compared with a mile; and the kilogram is large compared with a pound (500 g is sometimes used).
The purpose of this post is to explore a generic system of units that would be suitable for both everyday and scientific usage.
Start with temperature. For scientific purposes, the absolute minimum temperature is an important limit, so it should be set to zero or some multiple of 1000. The triple point of water is meaningful for both scientific and everyday usage. These two points suggest a scale with the absolute minimum set to –1000 degrees, and the triple point of water set to 0 degrees. One generic degree equals 0.27315 K. So a value of 100 equals 27 ºC or 81 ºF.
The day is a natural and everyday unit of time. It is traditionally divided into 24 hours, and further divided by 60 for minutes and seconds. A unit of time that is 1/1000th of a mean solar day would be a compromise unit for everyday and scientific purposes. So one generic time unit equals 1.44 minute.
As circular rotations are often used to represent time, so a full revolution would then be divided into 1000 degrees. So one generic degree of angle equals 3.6 degrees or about 0.006283 radians.
The speed of light is an important limit for science. The unit of length should be defined in terms of the travel distance during one generic unit of time at the speed of light. Since there are 299 792 458 m/s, a reasonable choice would be for the speed of light to equal 109 = 1 000 000 000 units of length per generic time unit.
That means one generic length unit equals 1.798754748 metres. So one thousand generic length units equals 1798.754748 metres, which equals 5901 feet – not that different from the 5280 feet in a mile.
Avogadro’s number is the number of atoms in one gram of hydrogen, which equals 6.02214076×1023. It makes generic sense to use a power of 1000 and use water as with the triple point.
Define one generic gram as 1×1024 molecules of water. There are 6.02214076×1023 molecules per mole. There are 18.0152 grams per mole of water. So there are 29.946 grams per generic gram. Ten generic grams equals 299.46 grams, which is not far from the 273 grams in a pound.
These generic units of measure are suitable for use in science and everyday life.
Addendum: the calendar
This approach can be applied to the calendar, too. The equinoxes and solstices naturally divide the year into four quarters. The beginning of the year would be one of these four, likely the vernal equinox in the northern hemisphere.
Twelve months is a smaller division that approximates the synodic lunar month of 29.5 days. The mean solar (tropical) year has 365.24217 days. Start with 30 days for each month. Add a day to one month each quarter, say the last month of the quarter. Add one day to the year, say the first month of the year. The result is months of 31, 30, 31, 30, 30, 31, 30, 30, 31, 30, 30, 31 days. Then follow the Gregorian leap year algorithm, with the leap day taken from the end of the year, with its mean year of 365.2425 days.