Newton's Laws of Motion

Brief insight of Newton's laws of motion.

Any science student or follower of Sir Isaac Newton (1643-1727) would know that his 3 laws of motion were framework for the mechanics of science. Newton calculated that the force of the attraction (gravity) between 2 objects is equal to the mass of each object multiplied by a gravitational constant and divided by the square of the distance between the objects.

What it means is that larger masses exert the stronger attraction, a reason why apples fall toward the Earth's gravitational centre. But, the force of gravity is reduced by distance - a reason why the Moon doesn't rush toward Earth or other larger celestial body. However, the earth's mass is much greater than that of the objects upon it that the force of attraction is large.

David E. Hughes and Carbon Microphone

Inventor of Carbon Microphone

English-born American David Edward Hughes is widely agreed as the inventor of the carbon microphone, a device important in the development of telephony. He also invented the induction balance for metal detectors and the printing telegraph system.

David Hughes was born in London, England on May 16, 1831. At the age of seven, he moved to the United States with his Welsh parents. In 1850, he became a music professor in Kentucky at the college of Bardstown. He later became a natural philosophy professor in the same school. Hughes only spent four years in the academic field, from where he began working on various devices, such as the type-printing telegraph and carbon microphone.

The Doppler Effect

It is extremely noticeable when police sirens or ambulance emergency vans rise in pitch as they approach us, and then eventually the pitch lowers down when they go off away from us into the distance.  This is referred to as Doppler effect.  More recently, the Doppler effect took centre-stage as investigators used it to trace the Malaysian aircraft Flight 370's disappearance.

The purpose of this post is to introduce in simple terms the concept of Doppler effect, what it is about and it's effect, and not to quantify intricate scientific formulations of frequency and the relationship of source and observer velocities.

Georg Ohm

German physicist who formulated Ohm's Law.

He worked on electric currents and acoustics. The unit of electrical resistance (Ohm) was named after him.
 
Georg Simon Ohm (16 March 1787 (89?) – 6 July 1854) was a German physicist born in Erlangen, Brandenburg-Bayreuth. He began his research as a high school teacher, used an electrochemical cell invented by Italian Count Alessandro Volta that time. Ohm taught in Cologne, Nuremberg, and finally in Munich.

A highly methodical experimenter, Ohm also availed his own created equipment to determine that there is a direct proportion between the potential difference (voltage) applied across a conductor and the resultant electric current.  This relationship is known as Ohm's law, an empirical law (found by experiment), which he formulated in 1827.

Watson, Crick and Wilkins: DNA and Genetics

Something about the DNA Structure and GENETICS

The structure of the DNA is considered one of the most profound discovery of the 20th century. DNA is the material that stores genetic information in chromosomes. By the time  Watson and Crick showed it was a "double helix," geneticists knew that it stored all the information needed for an organism to build and operate. 

DNA is short for deoxyribonucleic acid, a nucleic acid that contains the genetic instructions used in the development and functioning of living organisms.  The primary role of DNA molecules is the long-term storage of information.

Alessandro Volta

Science Dateline: February 18

Physicist Alessandro Volta, inventor of the battery

Alessandro (Giuseppe Antonio Anastasio) Volta was an Italian physicist known for the invention of the battery. He was born on February 18, 1745,  in Como, a town in present-day northern Italy near the Swiss border.

In 1774, he became a professor of physics at the Royal School in Como. He improved and popularized the electrophorus, a device that produced static electricity. He is often credited with its invention although a machine operating on the same principle was described in 1762 by Johan Wilcke, a Swedish experimenter.

Volta's Works

Volta studied the chemistry of gases between the years 1776-78. He discovered methane after reading a paper by Benjamin Franklin on "flammable air." In November, 1776, he found methane at Lake Maggiore. After two years he isolated it.

William Shockley

American Physicist, Inventor, and Nobel Laureate

William Bradford Shockley Jr. (February 13, 1910 – August 12, 1989), was an American physicist and inventor. He co-invented the transistor, along with John Bardeen and Walter Houser Brattain. All three were awarded the 1956 Nobel Prize in Physics.

Shockley's attempts to commercialize a new transistor design in the 1950s and 1960s led to California's "Silicon Valley" becoming a hotbed of electronics innovation. In his later life, he was a professor at Stanford and became a strong advocate of eugenics.

Emilio Gino Segrè

Emilio Gino Segrè discovered technetium andastatine and antiproton

Emilio Gino Segrè (1 February 1905 – 22 April 1989) was an Italian physicist and Nobel laureate who discovered the elements technetium andastatine, and the antiproton, a sub-atomic antiparticle, for which he was co-awarded the 1959 Nobel Prize in Physics with American Owen Chamberlain. An Antiproton is an antiparticle that has the same mass as a proton but opposite in electrical charge.

He was born in Tivoli, near Rome, and studied engineering at the University of Rome La Sapienza before taking up physics in 1927. Segrè was appointed assistant professor of physics at the University of Rome in 1932 and worked there until 1936. He was Director of the Physics Laboratory at the University of Palermo from 1936 to 1938.

Lars Onsager

Science / Scientist Datebook

Lars Onsager, Norwegian Chemist and Physicist

Credited for his discovery of the Onsager reciprocal relations, fundamental for the irreversible processes of thermodynamics.

Lars Onsager (November 27, 1903 – October 5, 1976) was a Norwegian-born American physical chemist and theoretical physicist, winner of the 1968 Nobel Prize in Chemistry. He held the Gibbs Professorship of Theoretical Chemistry at Yale University.

His research at Brown University was concerned mainly with the effects on diffusion of temperature gradients, and produced the Onsager reciprocal relations, a set of equations published in 1929. Two years later its form was expanded in statistical mechanics whose importance went unrecognized for many years. Their value became apparent during the decades following World War II. By 1968 they were considered important enough to gain him that year's Nobel Prize in Chemistry.

Wilhelm Konrad Röntgen

Scientists Datebook : March 27

German physicist Röntgen discovered X-Ray

Wilhelm Konrad Röntgen (1845-1923), German physicist was born March 27, 1845.  While teaching at Wuerzburg University in 1895, he discovered X-rays, for which he was awarded the first Nobel Prize in Physics in 1901.

Röntgen's (or Roentgen) name  is mainly associated with his discovery of the rays that he called X-rays. In 1895, sometime 8th of November, he discovers radiation emitted by cathode-ray tubes while conducting electrical experiments. He names them x-rays, with the "x" standing for "unknown."he was studying the phenomena accompanying the passage of an electric current through a gas of extremely low pressure.  Although previous works have already been carried out, his work on cathode rays led him to this discovery of a new and different kind of rays. Röntgen also worked on the heats of gases, in particular, the heat conductivity of crystals and electricity.

Frédéric Joliot-Curie

Frédéric Joliot-Curie, French physicist, shared Nobel Prize in physics with wife Irène Joliot-Curie,  for artificial radioactivity.

Frédéric Joliot ( (19 March 1900 – 14 August 1958) was born in Paris and graduated from the École Supérieure de Physique et de Chimie Industrielles de la Ville de Paris.  In 1925 he became an assistant to Marie Curie at the Radium Institute. He fell in love with her daughter Irène Curie, and married in 1926. At the insistence of Marie,  Joliot-Curie obtained a second baccalauréat, a bachelor's degree, and a doctorate in science, doing his thesis on the electrochemistry of radio-elements.

Frédéric and Irène changed their surnames to Joliot-Curie after they married on October 4, 1926 in Paris, France. Eleven months later, their daughter Hélène, was born, who would also become a noted physicist. Their son, Pierre, born in 1932, was a biologist.  Frédéric Joliot-Curie devoted the last years of his life to the creation of a centre for nuclear physics at Orsay, where his children were educated.

Galileo - the Astronomer, the Spacecraft, and the Satellite Navigation

What's in a name? It's Galileo!

The Galileo spacecraft mission and the Galileo satellite navigation projects are named after Galileo, founder of classical physics.

Galileo the Astronomer in a Nutshell

Galileo Galilei (b. Feb. 15, 1564, Pisa, Italy - d. Jan 8, 1642, in Arcetri, near Florence, Italy), was an Italian scientist - physicist and astronomer - founder of classical physics, and telescope inventor.

He was a professor at Pisa, who later moved to Padua and then to Florence. While studying medicine and through a hanging lamp in Pisa Cathedral, he deduced the formula for the swing of a pendulum. He later studied the laws of falling bodies, disproving Aristotle's view that the rate of fall is proportional to the weight.

Bragg's Law a Cornerstone of Crystallography

Bragg's Law: a cornerstone of the science of crystallography

In physics parlance, Bragg's Law gives the angles for coherent and incoherent scattering from a crystal lattice. The law was derived by physicist Sir William Lawrence Bragg in 1912 and first presented on 11 November of the same year to the Cambridge Philosophical Society. In mineralogy and crystallography, a crystal structure is a unique arrangement of atoms or molecules in a crystalline liquid or solid.

The Bragg's Law Equation:

Where n is an integer, λ is the wavelength of incident wave, d is the spacing between the planes in the atomic lattice, and θ is the angle between the incident ray and the scattering planes. Note that moving particles, including electrons, protons and neutrons, have an associated De Broglie wavelength.

Marie Skłodowska Curie

Science / Scientist's Datebook: November 7

 

Polish-French Chemist and Physicist, famous for pioneering work on Radioactivity    

      

Marie Curie 

 

Marie Skłodowska Curie (7 November 1867 – 4 July 1934), was born in Warsaw, Poland. She was a chemist and physicist famous for her pioneering work on radioactivity. Although her work brought about her death, it led to the discovery of cancer treatments, saving countless lives.

Marie Curie was married to a fellow scientist, Pierre Curie, and mother of Irène Joliot-Curie and Ève Curie. Despite being barred from higher education due to her sex, Curie pursued her studies at the clandestine "Flying University," where she laid the foundation for her revolutionary discoveries of radium, polonium, and the concept of radioactivity.

Irene followed in her parents' footsteps also becoming a Nobel laureate in Chemistry (1935) with her husband Frédéric Joliot-Curie. Eve (Ève Denise Curie Labouisse) was a writer, journalist and pianist. Ève was the only member of her family who did not choose a career as a scientist, however, her husband Henry Richardson Labouisse, Jr., American diplomat and statesman, collected the Nobel Peace Prize in 1965 on behalf of UNICEF.

Andrei Sakharov

Science / Scientist Datebook:  May 21

 

Sakharov a nuclear pioneer and activist for peace

Andrei Sakharov (May 21, 1921 - December 14, 1989), was a Soviet physicist and activist often referred to as the father of the Soviet hydrogen bomb. He was awarded the 1975 Nobel Peace Prize for advocacy of human rights and civil liberties, a nuclear pioneer who clamoured for peace.

Andrei (or Andrey) Dmitriyevich Sakharov was born in Moscow, Russia on May 21, 1921. The son of a physicist, he won a doctorate when he was 26 and became a full member of the Soviet Academy of Sciences by the age of 32. He spent several years working with Igor Tamm, a Nobel laureate for physics in 1958.

Initially, he studied cosmic rays before he became involved in the development of the Soviet H-bomb that was tested in 1949. Progressing his test, he moved to a more powerful hydrogen bomb research, tested in 1953.

Sakharov an Inspiration and Conscience of the Cold War

In 1961, Sakharov protested against Nikita Khrushchev's plan to test a 100-megaton hydrogen bomb designed to showcase the Soviet's world dominance. That was the time of the Cuban crisis and John Kennedy was U.S. president. Sakharov feared the effects of a radioactive fallout. In 1968, he published Progress, Coexistence and Intellectual Freedom, , an essay that called for the nuclear arms race to end. In 1971, he married the human rights activist, Yelena Bonner. The couple became increasingly at odds with the Soviet government. He denounced the Soviet adventure into Afghanistan and also called for a worldwide boycott of the Moscow Olympic Games.

In 1980, he was stripped of his honours and exiled to the city of Gorky.  Six years later, he was released and the Soviet government allowed the couple to return to Moscow.  In 1989 Sakharov was elected to the People's Congress, and his honours restored.  He died few months later, on December 14, 1989.

Andrei Sakharov was awarded the Nobel Peace Prize in 1975, for his work on human rights and civil liberties, a "spokesman for the conscience of mankind."



Image Credit:

Andrei Sakharov.   en.wikipedia.org (Wikimedia Commons)    



Resource:

"Andrei Sakharov - Autobiography". Nobelprize.org. 22 May 2012 http://www.nobelprize.org/nobel_prizes/peace/laureates/1975/sakharov-autobio.html. Accessed May 21, 2012.


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