New Units Of Measurement

This has been added to the compound posting "Measurement", November 2021.

Units of measure, for length, area, and so on, would be more useful if we could relate to them. This was originally the idea. The yard was based on the length of a king's arm. The mile was when the left foot of a marching soldier had touched the ground a thousand times. The meter was originally supposed to be one ten-millionth of the distance from the equator to the north pole, along the line of longitude that passes through Paris, but has since been redefined by wavelengths of light.

However most of this relatability has since been lost. Acres are widely used as a measure of land area. But how many people seriously know what an acre is? It started as the area that a farmer could usually plow in a day. Below is an acre against a nearby parking lot, where you can see the cars and parking spaces.

Image from Google Earth.

The modern era, particularly cars, has brought the possibility of a new set of units that are easily relatable to everyone. Units of length are the primary unit of measurement, being squared or cubed to form units of area and volume. In the Metric System mass is also based on length, and water, a liter of water weighs a kilogram.

When you turn on the heat or the radio in a car you probably turn a knob. These knobs seem to all be of a standard size and the width of one would make an ideal unit of measurement that everyone could easily relate to.

Then there is the steering wheel, which also come in standard sizes. This would be the most ideal and relatable length unit of all.

The next higher unit of length could be the width of a lane on a highway, again something that is very familiar to everyone.

We could form units of area by simply squaring the units of length. But probably the most familiar unit of area is also automotive in origin. What would be better for a general unit of area than a standard parking space?

Just another thought about measurement, but this is not related to cars. We now know that the universe overall is a very cold place. The average temperature in the universe overall is believed to be 2.726 degrees Kelvin, although that may not be an extremely precise figure.

Kelvin is the temperature scale that begins at Absolute Zero. Heat is the energy of moving atoms and molecules. When something cools down it's atoms and molecules move more slowly. If cooling continued so that all motion stopped it would not be able to get any colder. This point is known as Absolute Zero and is equivalent to -459 degrees Fahrenheit or -273.16 degrees Celsius.

The Celsius scale is defined by the melting and boiling points of water. Water freezes at zero degrees Celsius and boils at 100 degrees Celsius.

This means that the freezing point of water is at 273.16 degrees Kelvin, since a Kelvin degree is the same size as a Celsius degree. Notice that the average temperature of the universe is just about exactly one percent of the freezing point of water, starting at Absolute Zero, and the figure for the average temperature may not be perfectly accurate.

The size of a Celsius degree is one-hundredth of the span between the freezing and boiling points of water. Now that we are in the Space Age, and cosmology is becoming ever more important, why don't we define the average temperature of the universe as one degree? Water will then freeze at 100 degrees and boil at 136.89 degrees.

The freezing and boiling points of water are not as precise as it may seem. The freezing point depends on the purity of the water. The salt water in the sea does not freeze at zero degrees Celsius. The boiling point of water is dependent on the atmospheric pressure.