Tag Archives: Albert Einstein

Happy Pi Day

Happy Pi Day

 Happy Pi Day

When our son was in 3rd grade my husband taught him an easy way to remember the number for Pi.  Our son proudly went to school with his knowledge on Pi day, and when the teacher asked if anyone knew the number for Pi he raised his hand. She called on him and he said “How I Need A Drink”. She said, “well, then go to the water fountain.” And, being the obliging little fellow that he was, he went to the water fountain and got a drink, without ever bothering to explain that he was trying to tell her the mnemonic to remember Pi.

To remember the number Pi memorize the mnemonic  “How I need a drink, alcoholic of course, after the heavy lectures involving quantum mechanics,” The number  Pi correlates to the number of letters in each of the words in that sentence.

3.141 592 653 589 79…

(Instead of the word “alcoholic”, for the kids you can substitute “pepsicola”. Trust me from experience, it will save school teachers confusion.)

Pi day is celebrated on Einstein’s birthday because of the date and the meaning of the number. Pi is roughly the ratio of a circles circumference to its diameter, also representing the curvature of space/time to energy sources which is a basis in Einstein’s principal of relativity.

To learn more about Pi Day or Albert Einstein read the guest posts my father-in-law, a physics professor wrote  for Documama the past couple of Pi days.


It’s Pi Day!

It’s Pi Day!

“π-Day” (“Pi-Day”) Guest Post Written by Bulent Atalay

Ink drawing by the author, inspired by a Yousuf Karsh photo hanging in the Physics Department at Princeton University

Last year for “π-Day” (“Pi-Day”) I wrote a guest blog for Documama about Albert Einstein, Time Magazine’s choice for the “Individual of the 20th century.” The physicist, whose name has become synonymous with genius, was born in Ulm, Germany on March 14 (3.14) one hundred and thirty-four years ago. Frequently physics students have celebrated the day in homage to the birthday of the venerable scientist, and these days Pi-Day has become a bit more mainstream.

In his “miracle year,” 1905, Einstein had written four papers, three of which could have won the Nobel Prize. It was his paper with the most obscure title of all, “On the Electrodynamics of Moving Bodies,” that he changed the paradigm for physics that had prevailed since Isaac Newton published his masterpiece, the Principia, almost 230 years earlier. Better known as the “Special Theory of Relativity,” Einstein’s theory rejects the three fundamental undefinables of length, mass and time as being invariant, and in their place posits the speed of light as the unique invariant. Length, mass and time could increase or decrease, when the body travels at different velocities. Then ten years later he published his masterpiece, the “General Theory of Relativity,” which offered a refinement to Newton’s theory of gravitation. The Big Bang Theory, stars collapsing into black holes, quasars, pulsars… are all manifestations of the General Theory. Einstein’s legacy is as seminal, and as staggeringly consequential to the physicist’s understanding of physical reality as his theories are inscrutable to the non-physicist.


π is the symbol for the number representing the ratio of the circumference of a circle to its diameter. It is a universal constant, the same for all circles and indeed everywhere in the universe. In the language of mathematics, it is also an irrational number, and as such cannot be expressed exactly by the ratio of two numbers. Finally, it is also a transcendental number, that is, not algebraic — not a solution a non-zero polynomial equation with rational coefficients. A ramification of this last statement is that geometrically speaking “a circle cannot be squared,” a circle cannot be constructed with exactly the same area as a specified square using only a compass and a straight edge, and accomplished in a finite number of steps. The proof of this conjecture is so complicated that it was not achieved rigorously until 1882.

What Children are taught in elementary school:

Trick One:

A good approximation and an easy way to remember the number still comes from the mnemonic, “How I need a drink, alcoholic of course, after the heavy lectures involving quantum mechanics,” 3.141 592 653 589 79… Good to 15 places, it comes from counting the letters in each successive word. (For children, substitute “pepsicola” for “alcoholic”.)

Trick Two:

Again, π is the symbol for the number representing the ratio of the circumference of a circle to its diameter. At first pale, it is roughly equal to 3. Expressed to

photo from March 1926 National Geographic Magazine

two decimal places, it is 3.14. To seven places after the decimal, the correct value of π is 3.141 592 7 As an irrational number, however, π cannot be expressed exactly by the ratio of two numbers; however, elementary school students are often taught 22/7, as a crude approximation. The ratio yields 3.142 857, correct to just two places after the decimal.

The Ancient Egyptians building the Great Pyramid about 4600 years ago had the value of π to two decimal places, 3.14. After laying out a circle (points equidistant from a center), they measured its radius. Then they physically “squared the circle,” presumably by having four groups of workers pulling in four directions, with four equal sides and two equal diagonals. (This is not “squaring the circle” in the mathematical sense discussed in the last paragraph. The perimeters of the two figures are equal, but the areas encompassed by the two are not.) After the square base of the pyramid was laid out, then the radius of the original circle served was adopted as the height of the pyramid, 455 ft (139 m). The Great Pyramid, essentially a man-made mountain serving as a mausoleum for Pharaoh Khufu, rises at 52° relative to the plain of the base.

Trick Three:

Take the six integers 1 2 3 4 5 6, and subtract from them 0 1 0 1 0 1. Thus

1 2 3 4 5 6

 —0 1 0 1 0 1

1 1 3 3 5 5                                                                                                                                                             

Dividing the last three digits by the first three, 355/113, the ratio is obtained as 3.141 592 9. This is good to six decimal places.



About 1940 the π was computed to ten thousand significant figures.

In 1960, a computer was used to apply an algorithm to calculate π to one million decimal places, where it was found to terminate with 5.

In 2011, a most determined Japanese gentleman, Shigeru Kondo, collaborating with the Northwestern University graduate student, Alexander Yee, computed π to ten trillion places, where its value was found to be 5 again. This, however, is nothing more than a happy coincidence!

Bulent Atalay


Bulent Atalay is my brilliant father-in-law and a retired physics professor. He is also the author of two books, Math and The Mona Lisa, and Leonardo’s Universe. You can find out more about the amazing man my kids call Buyukbaba (Turkish for grandfather ) at his website  and on his blog for National geographic.


PI DAY (π-Day)

PI DAY (π-Day)

Ink Drawing by Bulent Atalay, inspired by a Yousuf Karsh photo of Einstein, hanging in the Physics Department at Princeton University

For Einstein’s birthday I asked my Father-In-Law, Bulent Atalay,  a theoretical nuclear physicist to write a guest post for Documama.

PI DAY by Bulent Atalay

Among physics students, March 14 is known as “π-Day” (“Pi-Day”) the day that Albert Einstein was born in Ulm, Germany in 1879. The venerable physicist is known for changing the very paradigm of physics, rejecting the three “fundamental undefinables”  — length, mass and time — as invariants, and positing in their place the speed of light as the unique invariant. (Thus, measuring the speed of a light beam while traveling in the same direction as the beam, and measuring it while traveling in the opposite direction would yield precisely the same relative velocities; this in distinction to common sense, which would call for adding and subtracting the speed of light from the speed of the observer.) The ramifications of this shift in paradigm lead to fascinating effects at relativistic speeds — including, a contraction of length, an increase of mass, and the slowing down of time. Lying down in the direction of motion in a rocket ship traveling at 50% of the speed of light, a 6′ man would shrink to 5’3”; if his weight were 180 pounds normally, it would increase to 207 pounds. And if he traveled for one earth-year, he would age 47 days less than if he had stayed stationary. Launched on March 14, 2012, and brought back one year later, on March 14, 2013, it would be only January 25, 2013 for him. Einstein’s special theory of relativity was published his 1905, and the far more complex general theory of relativity in 1915. The former gives the equivalence of energy and mass, in the most famous equation in science, E=mc^2. The latter, based on the equivalent effects of gravitation and acceleration, leads to explanations of the large-scale universe — a violent universe that has its origins in a “Big Bang,” 13.7 billion years ago; of light bending around massive bodies such as stars and galaxies; of stars that collapse into black holes; of “worm holes” that connect different locations of space-time in the universe. Isaac Newton’s dynamics, formulated two centuries earlier in the Principiaare still valid, but at relativistic velocities they have to be modified. Einstein’s work has to be regarded as buttressing Newton’s physics and not in any way subverting it. A spaceship can still be sent to land on the moon with Newton’s physics, but Einstein’s corrections would make it a softer landing.

Albert Einstein

Late in 1999, the editors of Time Magazine, used to selecting the “Individual of the Year,” found themselves with a much more difficult task — selecting the individual of the century. After what must have called for considerable deliberation, they made their announcement. It would not be a spiritual leader, such as Pope John Paul II, Gandhi or Mother Teresa. And it would not be a world leader, such as FDR, Stalin or Churchill, in a century that had seen two World Wars. The editors’ choice for the “Individual of the Century” would be Albert Einstein. They explained the reasoning in their selection: the 20th century had been the ‘Century of Science’ and Albert Einstein was its greatest practitioner, and the very symbol of science.



POSTSCRIPT. π, is the irrational number corresponding to the circumference of a circle divided by the diameter. To seven places after the decimal, its value is 3.141 592 7 As an irrational number π cannot be expressed exactly by the ratio of two numbers, however, elementary school students are often taught 22/7, as a crude approximation. It yields 3.142 857, good to two places after the decimal. A much better approximation is 355/113, a ratio that equals 3.141 592 9, good to six places. A better approximation still comes from the mnemonic, “How I need a drink, alcoholic of course, after the heavy lectures involving quantum mechanics,” 3.141 592 653 589 79…, i.e. by counting the letters. (Rather than “alcoholic”, for the adolescents substitute “pepsicola”.)


For more about Bulent Atalay and his work visit his website:  www.bulentatalay.com  or

read more of his blog posts at http://newswatch.nationalgeographic.com/author/drbatalay/