Wednesday April 7, 2021’s Smile of the Day: The Metre

On this Day:

In 1795, France adopted the metre as the basic measure of length.

The metre (Commonwealth spelling) or meter (American spelling)  is the base unit of length in the International System of Units (SI). The SI unit symbol is m.

The metre is currently defined as the length of the path travelled by light in a vacuum in 

1/299 792 458 of a second.

The metre was originally defined in 1793 as one ten-millionth of the distance from the equator to the North Pole along a great circle, so the Earth’s circumference is approximately 40000 km. In 1799, the metre was redefined in terms of a prototype metre bar (the actual bar used was changed in 1889). In 1960, the metre was redefined in terms of a certain number of wavelengths of a certain emission line of krypton-86. The current definition was adopted in 1983 and modified slightly in 2002 to clarify that the metre is a measure of proper length.

The length of a metre has changed over the years:

8 May 1790, the French National Assembly defined The length of the new metre to be equal to the length of a pendulum with a half-period of one second.

30 Mar 1791, the French National Assembly  accepts the proposal by the French Academy of Sciences that the new definition for the metre be equal to one ten-millionth of the length of a great circle quadrant along the Earth’s meridian through Paris, that is the distance from the equator to the north pole along that quadrant.

10 Dec 1799, the French National Assembly specifies the platinum metre bar, presented on 22 June 1799 and deposited in the National Archives, as the final standard. Legally equal to 443.296 lines on the toise du Pérou.

24–28 Sept 1889, the 1st General Conference on Weights and Measures (CGPM) defines the metre as the distance between two lines on a standard bar of an alloy of platinum with 10% iridium, measured at the melting point of ice.

27 Sept – 6 Oct 1927, the 7th CGPM redefines the metre as the distance, at 0 °C (273 K), between the axes of the two central lines marked on the prototype bar of platinum-iridium, this bar being subject to one standard atmosphere of pressure and supported on two cylinders of at least 10 mm (1 cm) diameter, symmetrically placed in the same horizontal plane at a distance of 571 mm (57.1 cm) from each other.

14 Oct 1960, the 11th CGPM defines the metre as 1650763.73 wavelengths in a vacuum of the radiation corresponding to the transition between the 2p10 and 5d5 quantum levels of the krypton-86 atom.

21 Oct 1983, the 17th CGPM defines the metre as the length of the path travelled by light in a vacuum during a time interval of 

1/299 792 458 of a second.

2002, the International Committee for Weights and Measures (CIPM) considers the metre to be a unit of proper length and thus recommends this definition be restricted to “lengths ℓ which are sufficiently short for the effects predicted by general relativity to be negligible with respect to the uncertainties of realisation” (per Wikipedia).

First, a Story:

What do you call a snake that’s 3.141592653589793.. meters long?  A π-thon

Second, a Song:

“Go the Distance” is a song from Disney’s 1997 animated feature film, Hercules. It was written by composer Alan Menken and lyricist David Zippel, and originally recorded by American actor Roger Bart in his film role as the singing voice of Hercules. American singer-songwriter Michael Bolton recorded a pop version of the song for the film’s end credits, which was also included on his 1997 album All That Matters. In the Spanish version, the song is performed by Hercules voice actor Ricky Martin, both in the movie and in the credits; this version is included on Martin’s album Vuelve. Both the song and its reprise featured in a stage production of Hercules, performed upon the Disney Wonder during 2007/2008.

Michael Boltin (born February 26, 1953), known professionally as Michael Bolton, is an American singer and songwriter. Bolton originally performed in the hard rock and heavy metal genres from the mid-1970s to the mid-1980s, both on his early solo albums and those he recorded as the frontman of the band Blackjack. He became better known for his series of pop rock ballads, recorded after a stylistic change in the late 1980s.

Bolton’s achievements include selling more than 75 million records, recording eight top 10 albums and two number-one singles on the Billboard charts, as well as winning six American Music Awards and two Grammy Awards (per Wikipedia).

Here is a mash up of scenes from Hercules set to “Go The Distance” performed by Michael Bolton.  I hope you enjoy this!


Thought for the Day:

A To’fer:

Topology is a branch of mathematics that concerns itself with the abstraction of the concept of distance. My old topology professor, Dr. Marlon Rayburn, put it thus:  “No matter how far you are away from your mother-in-law, she is always too near”.


“Laughter is the closest distance between two people.” – Victor Borge

Have a great day!

Dave & Colleen

© 2021 David J. Bilinsky and Colleen E. Bilinsky

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