# Liberal Arts Blog — The “Seven Defining Constants” — Seven Little Miracles — A Hidden Metaphor

Liberal Arts Blog — Monday is the Joy of Math, Statistics, Shapes, and Numbers Day

Today’s Topic: The “Seven Defining Constants” — Seven Little Miracles — A Hidden Metaphor

Humans yearn for stability and predictability in life. Isn’t it wonderful, and supremely comforting that there are “seven defining constants”? I’m not referring to the certainty that the sun, the moon, and the stars will rise and fall, but to those seven magic constants of the International System of Units. Each of the seven basic units (second, meter, kilogram, kelvin, ampere, mole, and candela) has one! How very fair! No one was left out! This morning I decided to learn a little more about each. There is a metaphor here. No agreement on basic premises and units of measure, no serious conversation.

Experts — please chime in. Correct, elaborate, elucidate.

THE METER, THE KILOGRAM, AND THE SECOND — can you guess what the constants are? who cares? who should? a 5th grader? an 8th grader? a 12th grader? a Harvard graduate?

1. The Meter: the defining constant is the speed of light! (in a vacuum). “Nothing in the cosmos — matter, information, energy — can travel faster than the speed of light.” The symbol of the speed of light is “c.” The number is 299,792,458 meters per second.

2. The Kilogram: the Planck constant “h”. “Quantum mechanics shows us that energy is exchanged and absorbed in specific amounts, known as “quanta.” *h* defines the size of those quanta, which can be visualized as packets of energy exchanged by matter. *h* is equal to exactly 6.626 070 15 × 10–34 Joule seconds.” (A joule is the amount of work done when a force of one newton displaces a mass of one kilogram the distance of one meter.)

3. The Second: well this one is really tough. It’s called the “hyperfine transition frequency of Cesium-133" which to me is totally confusing. Its symbol is the triangle followed by a v in the circle above. Sometimes a subscript of “Cs” is added. Its value is 9,192,631,770 hertz. Got that? Let’s see if this helps. Cesium-133 is the most common isotope of the element Cesium which is metallic. “Like all atoms, cesium is orbited by electrons. The energy of cesium’s outermost electron can be controlled with microwave radiation. The frequency of microwave radiation that causes this electron to jump between two closely spaced low-energy states is known as the hyperfine transition frequency.” Still confused? Maybe the 3:27 video in the third link below will help. But it could just make this worse.

THE AMPERE (electric charage) AND THE KELVIN (temperature)

1. Ampere: “*e *is the amount of charge in an electron. It’s connected to electromagnetism, one of the four forces of nature. In the revised SI, *e* is equal to 1.602176634 × 10–19 coulombs.” Don’t confuse this “e” with the mathematical constant “e” (Euler’s number) which is a very boring “2.71” roughly. By the way, a coulomb is the amount of electricity conveyed in a second by one ampere….Hmm.

2. Kelvin: “k” — The Boltzmann constant “relates an object’s energy to its temperature. In the revised SI, the Boltzmann constant *k* equals 1.380649 × 10–23 joules/kelvin.”

THE MOLE AND THE CANDELA

1. Mole: 6 X 10 raised to the 23 power. How many moles of gratitude do you have? courage? prudence? perseverance? joy? curiosity? imagination?

2. Candela: now this will blow your mind. K with a subscript cd is the “luminous efficacy of Monochromatic radiation of frequency 540 × 1012 hertz” which is “simply green light, specifically the shade of green light that the human eye can pick up most sensitively in a well-lit room. And “luminous efficacy” is basically the total amount of visible light that a source produces using a certain amount of power. Kcd is equal to 683 lumens per watt and helps to define the candela.”

International System of Units — Wikipedia

https://en.wikipedia.org/wiki/Caesium

QUOTE OF THE MONTH

“Whenever you are wrong, admit it. Whenever you are right, shut up.” - Ogden Nash

ATTACHMENTS BELOW:

#1 A graphic guide to justice (9 metaphors on one page).

#2 “39 Songs, Prayers, and Poems: the Keys to the Hearts of Seven Billion People” — Adams House Senior Common Room Presentation, 11/17/20

PDF with headlines — Google Drive

YOUR TURN

Please share the coolest thing you learned this week related to math, statistics, or numbers in general. Or, even better, the coolest or most important thing you learned in your life related to math.

This is your chance to make someone else’s day. And to consolidate in your memory something you might otherwise forget. Or to think more deeply than otherwise about something dear to your heart. Continuity is key to depth of thought.