Happy Birthday Monsieur Pascal

Blaise Pascal was born June 19, 1623 in Clermont-Ferrand, France. Pascal was a truly great mathematician, physicist, and philosopher. I see his name all the time in my work because the SI unit of pressure is the pascal.

Over at Rationally Speaking Massimo Pigliucci has a post with a nice quote from Monsieur Pascal.

Men never do evil so completely and cheerfully as when they do it from religious conviction.

The Wikipedia entry for Monsieur Pascal I find to be excellent so I’ll send you there for more about this giant of science.

Ohm's Birthday

The science giant whose shoulders I stand on the most, was born today, March 16 in 1789. Georg Simon Ohm was born to Johann Wolfgang and, Maria Elizabeth Ohm in Erlangen, Bavaria (now part of Germany). His father was a locksmith who taught his self advanced mathematics and science. Johann provided his children with an education in math and science superior to what was available in schools of the time. Georg drifted around a bit in his studies and was not very successful in earning a living from 1805 when he entered university until October 1811 when he received a doctorate from the University of Erlangen.

Georg’s work on electromagnetism began around 1825 and led to his publication of one of the fields most important books in 1827. The book, “The Galvanic Circuit Investigated Mathematically” contains what we now call Ohm’s Law. This elegant equation, E=IR, was a breakthrough in electromagnetism that was not widely accepted for many years. Ohm was awarded the Royal Society’s Copley Medal in 1841 and became a foreign member in 1842. He died July 6th 1854 in Munich Germany.

In recognition of Georg Ohm’s tremendous contribution to science the SI unit for electrical_resistance was named the ohm. In combination with Kirchhoff’s circuit laws, Ohm’s law provides the foundation for so much electronics design that I use it nearly every day in one way or another. So Happy Birthday to Georg Simon Ohm the biggest of my personal giants.


Heinrich Hertz Birthday

On February 22 in 1857 Heinrich Rudolf Hertz was born in Hamburg, Germany. His work in electromagnetism was important in advancing the state of physics at the end of the 19th century. In particular his modifying of Maxwell’s equations was instrumental in advancing the study of radio waves. Hertz’s experiments proved predictions made by Faraday and Maxwell and showed that radio waves move at the speed of light.

In recognition of Hertz’s great contributions, the SI unit for frequency was named hertz in 1960. The hertz replaced cycles per second (cps) and is now so common that most people are familliar with it as a unit of measurement.
The Wikipedia biography I found to be exceptionally well done with good links to further reading. The one addition I have is a link to an English translation of his book Electric Waves: Being Researches on the Propagation of Electric Action with Finite Velocity. This translation contains a preface written by Lord Kelvin.

Repost of last years birthday post

Happy Birthday Count Volta

Alessandro VoltaToday is the birthday of Count Alessandro Giuseppe Antonio Anastasio Volta. He was born February 18, 1745 in Como, Lombardy, Italy to Filippo Volta and Maria Maddalena Inzaghi. Volta became the first professor of physics at the University of Pavia in 1779 and held that position for much of his adult life. In March 1800 Volta announced his invention of the voltaic pile, the first electric battery. In recognition of Volta’s scientific contributions, the SI unit for electric potential difference (aka, electromotive force) was named the volt in 1881.


Wikipedia SI unit – volt

Re-posted from last years birthday celebration

James Thomson's Birthday

James Thomson was born February 16, 1822 in Belfast Ireland, he was the first son of James and Margaret Thomson. His mother, Margaret Gardner Thomson died in 1830 so his father James raised their seven children alone. In 1832 his father took up the Chair of Mathematics at Glasgow University and two years later at the age of twelve James and his younger brother William began studying at the university. James graduated in 1839 and began his apprenticeship as a civil engineer but do to health reasons decided he was not cut out for the hard physical labor common to civil engineers of the day. So beginning around 1843 he devoted himself to inventing machines and theoretical studies making many contributions to physics and engineering. He was living in Belfast when in 1857 he became Professor of Civil Engineering at Queen’s College. He stayed in Belfast until 1873 when he accepted the Glasgow University Regius Chair in Civil Engineering. He remained at the University of Glasgow until 1889 and died May 8, 1892.

While James Thomson had many achievements including helping his brother William (Lord Kelvin) he caught my eye because of the radian. The term radian was used in print for the first time by James on June 5, 1873 in examination questions he wrote at Queen’s College. He also helped spread the adoption of this unit of measurement in consultations with other scientists and engineers. (See A History of Mathematics By Florian Cajori, page 484) He is also credited with the invention of the non-SI unit the poundal.

The radian is the SI derived unit of measurement for a plane angle. Most people are more familiar with degrees for measuring angles however, the radian is extremely important because it encapsulates the value of PI. PI, the ratio of a circle’s circumference to its diameter is an irrational real number that can create a mess in formulas when degrees are used for the angle measurement.

So, lets raise a glass and toast James Thomson, MA, DSc, LLD, FRS for being a giant on who’s shoulders we can all stand!

References and further reading:
Dictionary of Ulster Biography
Who, Where and When: The History & Constitution of the University of Glasgow [pdf]
His father
1911 Encyclopedia Britannica
1911 Encyclopedia Britannica

The radian
Angle measurement
Radian Measure
A History of Mathematics By Florian Cajori
Origin of Radians

Ampère's Birthday

andremarieampereAndré-Marie Ampère was born in Lyon, France on January 20th, 1775. He was a physicist, mathematician, chemist and natural philosopher who made significant contributions in all these fields. Ampere’s work in understanding electromagnetism are recognized by naming the SI unit of electric current the ampere.

University of St Andrews
Catholic Encyclopedia
National Imports LLC
@ Google Books:
A Short History of Natural Science …
Derivation of Practical Electrical …

Ampere Portraits:
University of St Andrews
Wikimedia Commons

Happy Birthday Celcius

Anders Celsius was born on November 27th, 1701 in Uppsala, Sweden. If you don’t already know and love the Celcius temperature scale (previously known as centigrade) then you must be a US citizen and have not studied any technical subjects in depth. 😉 The commonly used SI derived unit for temperature is named Celsius in his honor. There are many good biographies available on the web so, I won’t write up a separate one here, see the following links.


History of astronomy in Uppsala

The Sky over Berlin

Project Galactic Guide




Other Articles about Celcius:

Celsius – Wikipedia

Daniel Fahrenheit, Anders Celsius Left Their Marks, Alaska Science Forum

Who Invented the Thermometer – Fahrenheit Celsius and Kelvin Scales.

Happy Birthday Hans Oersted

orstedHans Christian Ørsted (Oersted) was born August 14, 1777 in Rudkøbing (Rudkjobing), Denmark (island of Langeland). Oersted received a doctor of philosophy degree in 1799 from the University of Copenhagen. Like many of the great scientists of late 18th and early 19th centuries, Oersted studied many fields including chemistry, aesthetics and physics. In addition to his scientific work he also was a published writer and poet.

The discovery that puts Oersted on my list of giants was the connection between electricity and magnetism. The details of how this discovery happened are uncertain with three accounts by Oersted as well as information from students who were present at the time. See the biographies and articles linked below for some of the variations in the story. What seems clear to me is that although he was not specifically experimenting with a compass near a wire carrying an electrical current, he immediately recognized the significance of the observed effect. Oersted had seen the compass needle move and through later experiments and analysis demonstrated clearly the deep connection between electricity and magnetism, what we refer to today as electromagnetism. For this important work he received the prestigious Copley Medal from the Royal Society of London in 1820. His work was recognized in 1930 by naming the SI unit of magnetizing force (magnetic field strength) the oersted.

Eric Weisstein’s World of Scientific Biography

Oersted and the Discovery of Electromagnetism by Frederick Gregory, Department of History, University of Florida
Oertsted and Ampere by Dr. David P. Stern

Coulomb's Birthday

Charles Augustin de Coulomb was born on June 14th 1736 in Angouleme, France. Coulomb worked as a military engineer for 20 years after graduating from the military school at Mezieres in 1761. During this time when most engineering involved only practical numerical solutions he applied physics and mathematics to the study of mechanical engineering problems. While the advanced solutions weren’t applied by many of his engineering peers, they were instrumental to the rapid advancement of mechanics in the following centuries.

The enormous body of work produced by Coulomb over the next twenty years includes major advances in our understanding of electricity and magnetism. His work during this period that most impacts my job was the development of Coulomb’s law. To honor this great engineer and scientist, the SI unit for electric charge is named the coulomb.

University of St Andrews