Physics Notes - Herong's Tutorial Notes - v3.24, by Herong Yang
Meter Based on Seconds Pendulum
This section introduces an old definition of 'meter' which uses a seconds pendulum. A 'meter' is the length of a seconds pendulum, which swings a full cycle in 2 seconds in small angles.
The French National Assembly also accepted another definition of 'meter' to be "the length of a pendulum with a half-period of one second" in year 1790.
This definition is based on the factor that a small angle pendulum with a half-period of one second will have a length of about one meter, as illustrated in the picture below:
Since "meter" is defined more accurately now with the speed of light, the accurate length of a seconds pendulum at the sea level is 0.994 meter.
With this knowledge, you can actually create your own 1 meter string as a measuring tape.
Table of Contents
Meter Based on Earth's Meridian
►Meter Based on Seconds Pendulum
Meter Prefixes and Other Units
List of Various Distances and Lengths
Introduction of Frame of Reference
Introduction of Special Relativity
Time Dilation in Special Relativity
Length Contraction in Special Relativity
The Relativity of Simultaneity
Minkowski Spacetime and Diagrams
Introduction of Generalized Coordinates