Measurement of space and time

Here is a roundup of various instruments and methods for measuring space and time that may be stopped or continued indefinitely:

A bematist (from ancient Greek βῆμα bema ‘pace’) was a specialist in ancient Greece who was trained to measure distance by counting their steps.

An odometer for measuring distance was first described by Vitruvius (c. 27 – 23 BC) although the actual inventor may have been Archimedes of Syracuse (c. 287 – 212 BC). The odometer of Vitruvius was based on chariot wheels of 4 feet (1.2 m) diameter turning 400 times in one Roman mile (about 1400 m).

In 1903 Arthur P. and Charles H. Warner from Beloit, Wisconsin, introduced their patented Auto-meter, which used a magnet attached to a rotating shaft to induce a magnetic pull upon a thin metal disk. Measuring this pull provided automobile drivers with accurate measurements of both distance and speed in a single instrument.

A measuring wheel or surveyor’s wheel is a wheel attached to a handle that can be pushed or pulled along by a person walking to measure distance traveled. It is marked in fractional increments of revolution from a reference position. If the wheel is rotated a full turn, the distance traveled is equal to the circumference of the wheel. Otherwise, the distance the wheel traveled is the circumference of the wheel multiplied by the fraction of a full turn.

A trip meter (tripometer) is an odometer that may be reset to record the distance traveled in a particular journey or part of a journey.

A ruler (aka rule or line gauge) is a straightedge with calibrated lines at specified distances from one edge to measure distances or lengths. A tape measure or measuring tape is a flexible ruler, designed to be rolled up for portability.

A clock (or timepiece) is any device for measuring and displaying the time that is designed not to stop. It is one of the oldest human inventions, meeting the need to consistently measure intervals of time shorter than the natural units: the day, the lunar month, and the year.

All oscillating clocks, mechanical and digital and atomic, work similarly and can be divided into analogous parts. They consist of an object that repeats the same motion over and over again, an oscillator, with a precisely constant time interval between each repetition, or ‘beat’. Attached to the oscillator is a controller device, which sustains the oscillator’s motion by replacing the energy it loses to friction, and converts its oscillations into a series of pulses. The pulses are then counted by some type of counter, and the number of counts is converted into convenient units. Finally some kind of indicator displays the result in human readable form.

A stopwatch is a clock that can be started and stopped easily.

Note that the ability of a measuring device to operate continuously is irrelevant to its utility for measuring the dimensions of or to an object or event. Alternatively, an odometer or other rotation-based distance measuring device could be operated continuously. The conclusion is that there is no necessary connection between time or space and continuous change or movement.