Pages

Saturday, May 18, 2013

famous physicists (2)

 famous physicists (2)


Lord William Thomson Kelvin (1824 - 1907)

He not only formulated the first and second Law of Thermodynamics, but also had improved the reliability of the mariner's compass. Due to his maritime interests, he became involved with the transatlantic telegraph project and was knighted by Queen Victoria, after which he became Sir William Thomson. He was the one who put forth the correct value of absolute zero as -273.15 celsius. Also, in his honor, unit of absolute temperature is known as 'Kelvin'.

Heinrich Hertz (1857 - 1894)

He was the pioneer who proved the existence of electromagnetic waves. The term 'Hertz' was named in his honor as the unit of frequency. He had published several papers and articles on diverse topics like meteorology and contact mechanics.

Lord Ernest Rutherford (1871 - 1937)

He is also known as the father of nuclear physics. He was one who stated that whenever there is radioactivity, the chemical element emitting the radiowaves undergoes transmutation from one form to another. He differentiated the emitted radiations and named them as alpha and beta. He had also put forth the famous Rutherford model of atom in 1911.

Nikola Tesla (1857 - 1943)

Tesla worked for Thomas Edison before starting his own chain of laboratories that developed electrical devices. He holds a patent for alternating current induction motor. It is believed that Tesla is the first person in North America who accidentally captured an X-ray image.

John Dalton (1766 - 1844)

Dalton is the pioneer of modern atomic theory. He put forth the five main points of the atomic theory, one of which said that atoms cannot be created or destroyed but can be combined, separated or re-arranged. Dalton's law of partial pressure was put forth in 1801, and has now become very valuable in the chemistry lab.

Daniel Gabriel Fahrenheit (1686 - 1736)

The everyday household mercury thermometer was developed by him. He also determined the temperature scale called Fahrenheit, which was named after him. The Fahrenheit scale has undergone alterations, and now the body temperature is taken as 98.6 degrees, as opposed to the initial 96 degrees.

Blaise Pascal (1623 - 1662)

His inventions include the first calculation machine know as the Pascal's calculator (later Pascaline), which he constructed at the age of eighteen. His other inventions were hydraulic press, followed by a syringe. He had demonstrated exceptional grasping ability at a very young age, which his father had noticed, and kept him at home so that he does not get overworked.

Christian Doppler (1803 - 1853)

Now called the doppler effect or the doppler shift, this theory laid the foundation for the sonar and radar. The theory says, that the observed frequency of any type of waves is dependent on the speed of the source and observer. He had rightly said that his theory would someday help the astronomers to measure the distances and speed of the stars.

Satyendra Nath Bose (1894 - 1974)

Bose hailed from India. While giving a lecture to his students, he realized that there is a discrepancy in the theory of radiation. Thus, he wrote a letter to Albert Einstein, stating the discrepancy. Einstein agreed and extensively worked upon his idea, which led to the development of Bose-Einstein condensate. After that, many related concepts like bosons, Bose-Einstein statistics came into existence.

James Prescott Joule (1818 - 1889)

Joule studied how heat was related to mechanical work. The first law of thermodynamics was born out of this relationship. To honor his work, the SI unit of energy, 'Joule', is named after him. He also put forth the Joule's law, worked in close collaboration with Lord Kelvin, and carried out some investigations on magnetostriction.

Nobel Laureates

Wilhelm Conrad Rontgen (1845 - 1923)

It was on 8th November 1895, that Rontgen detected a specific wavelength of electromagnetic radiation now known as X-rays. This discovery helped him bag the Nobel prize in 1901. Also, a very radioactive element, Roentgenium, was named after him to honor his achievements.

Pierre Curie (1859 - 1906) and Marie Curie (1867 - 1934)

A pioneer of radioactivity, piezoelectricity and magnetism, he shared his Nobel prize, received in 1903, with his wife Marie and Prof. Henri Becquerel, for their contribution to the radiation phenomena discovered by Professor Henri Becquerel. He also put forth the Curie's law, which shows the effect of temperature on paramagnetism. Pierre, along with his wife Marie, were the first to use the term 'radioactivity' and successfully isolated 'polonium' and 'radium'. The unit of radioactivity, 'Curie', is also coined after their names.

Antoine Henri Becquerel (1852 - 1908)

Becquerel shared his Nobel with doctoral student Marie Curie and her husband Pierre Curie. His interest in phosphorescence led to his discovery that when uranium salts are illuminated by bright sunlight, they emit penetrating X-ray like rays. But these rays differed from X-rays in the property that they could be bent by electric or magnetic fields. Later, discovery of a few more radioactive elements like thorium etc., was done.

Lord Rayleigh (1842 - 1919)

He earned the Nobel prize for his discovery of argon gas in 1904. But there was another phenomenon called 'Rayleigh scattering' which was discovered by him. 'Rayleigh waves', that travel on the solid surfaces, were also discovered by him. He was an outstanding scientist whose work ranged over almost all the fields of physics.

Johannes Diderik van der Waals (1837 - 1923)

He established the equation of state for liquids and gases that describes the behavior of gases and their condensation on the liquid phase. He received the Nobel prize in 1910. Some more terms like, 'van der Waals forces', 'van der Waals molecules' and 'van der Waals radii' are coined after his name to honor his accomplishments.

Max Planck (1858 - 1947)

Planck established the Quantum Theory, that earned him the Nobel prize in 1918. He had made several other contributions to physics, but this theory reformed the human understanding of atomic and sub-atomic activities. It was one of the fundamental theories on which physics rests.

Albert Einstein (1879 - 1955)

A stalwart, who needs no introduction, Einstein put forth one of the pillars of modern physics, 'General theory of Relativity'. E=mc2 has been dubbed as the 'world's famous equation', and it also earned him a Nobel prize in 1921. In his lifetime, he published nearly 300 scientific papers. His exceptional wisdom has made the word 'Einstein' synonymous with 'intelligence'

Niels Bohr (1885 - 1962)

He put forth the theory of nuclear reactions and nuclear fission. His foundational contributions in the field of quantum mechanics earned this ardent football player a Nobel prize in 1922. It was Bohr who showed to the world that nucleus lies in the center and the electrons revolve around it, just like the sun and the planets revolving around it.

Sir Chandrasekhara Venkata Raman (1888 - 1970)

His research on scattering of light and establishing the Raman effect got him a Nobel prize in 1930. He was an Indian physicist, who helped India grow by his influential work. He was the founder and editor of 'The Indian Journal of Physics'. He also carried out many other investigations, and also approached the basic problems of crystal dynamics with a different mindset.

James Chadwick (1891 - 1974)

Discovery of neutron was his path-breaking discovery that helped him bag the coveted Nobel in 1935. Neutrons lacked electrical charge and therefore, were not required to overcome the coulomb barrier, that makes it easy for them to penetrate the nuclei of the heaviest element. This was important for the understanding of the nuclear fission of Uranium 235.

Carl David Anderson (1905 - 1991)

While studying the energy distribution of cosmic-rays for his doctoral thesis, he discovered positron (positive electron) which bagged him the Nobel prize in 1936. He had many honors bestowed upon him, apart from the Nobel.

Wolfgang Pauli (1900 - 1958)

Establishing the Pauli principle, which is also called the exclusion principle, Pauli received the Nobel prize in 1945. He was nominated for the Nobel by Albert Einstein. His major contribution was in the field of 'quantum mechanics.' Pauli often kept his work unpublished, due to which much of his work went uncredited.

Dennis Gabor (1900 - 1979)
He discovered holography in 1947, for which he received the Nobel prize in 1971. However, it became commercially available only after 1964. Granular synthesis was another finding of Gabor, which was not related to his original field of study. It was the result of his investigations on how human beings communicate with each other and hear the voices. This work of his was radical for the development of time-frequency analysis.

famous physicists (1)

 famous physicists (1)

 

Galileo Galilei (1564 - 1642)

An Italian genius, Galileo created the telescope and observed the galaxy in so much depth, that his ideas were deemed irrational. He not only discovered the phases of Venus, the four satellites of Jupiter: Io, Europa, Callisto, and Ganymede, but also proved that the ocean tides were caused due to the gravitational pull of the moon and not due to the earth's rotation. Compass and thermometer were also his inventions. This stalwart, who had magnified the galaxy a thousand times for us, died after he had turned completely blind.

Willebrord Snellius (1580 - 1626)

His Law of Refraction was published 70 years after he died. He had discovered that light bends when it falls on any material, and the angle at which it bends depends on the angle of its incidence. This Law of Refraction is called the Snell's law.

Robert Hooke (1635 - 1703)

Hooke's Law of Elasticity puts forth the relationship between the force applied to an object and the level of deformation it undergoes. Also, Hooke was the first person to observe the plants and fossils under a microscope, and coin the term 'Cell'. In 1665, he published his book named 'Micrographia', in which he had put forth some of his original observations of biology.

Christian Huygens (1625 - 1695)

He had put forth the wave theory, which said that if a wave is traveling at a particular speed, then all the points on the wavefront serve as sources for new wavelets, which would travel at the same speed.

Sir Isaac Newton (1643 - 1727)

Newton's Laws of Motion and universal gravitation laid the foundation for most of the modern physics. He was not only a physicist but also a Mathematics wizard. With equal originality, he also immersed himself in chemistry and left a few manuscripts on the subject, which later served as a base for the future scientists to develop on.

Benjamin Franklin (1706 - 1790)

He was an American physicist who discovered two electric charges, 'positive' and 'negative'. Franklin was a fantastic inventor who never patented any of his inventions. Even today, his famous invention of the lightning rod, protects many buildings and ships from getting damaged by lightning. He was a versatile personality, being an author, satirist, diplomat, statesman, politician and musician, all into one.

Charles-Augustin de Coulomb (1736 - 1806)

Coulomb's Law was one of his greatest contribution to physics. He invented a device called 'torsion balance' with the help of which, he measured the force of attraction or repulsion between two charged bodies. After exhaustive research and huge amount of findings, he finally put forth the fundamental Coulomb's Law of electromagnetism.

James Watt (1736 - 1819)

While repairing a damaged steam engine, Watt found out that it was hopelessly inefficient and tried to improve its design. He tried to minimize the steam losses by designing a condensing chamber for the steam. This design made the machine more cost-efficient and also improved its power. While the SI unit of power, 'Watt', is named after him, the concept of 'horsepower' was also his brainchild.

André-Marie Ampère (1775 - 1836)

Rightly known as the Father of Electrodynamics, the SI unit for measuring current, 'Ampere', is named after him. He was the one who laid the foundation of electrodynamics. The galvanometer was his invention, and he stated that it can be used for measuring the magnitude of current by the deflection of the compass needle, caused by a flowing electric current. He not only made giant strides in physics, but also mathematics and chemistry.

Amedeo Avogadro (1776 - 1856)

As a tribute to his work, a constant was named after him. Avogadro's constant or number (6.0221415 x 1023) is the number of elementary entities like the atoms, ions, molecules present in 1 mole of a substance. Another contribution of Avogadro was the law which stated that 'same number of molecules are present in equal volumes of gas at equal temperature and pressure'. He was the one who helped solve the debate on what an atom or molecule is.

Georg Ohm (1776 - 1856)

While in school, Ohm was more interested in dancing, ice skating and playing billiards, than studying. He received recognition very late in his life, because of his mathematical approach to topics, in the time when people approached them in a non-mathematical way. Also, he was an introvert. In spite of these shortcomings, Ohm became a household name today for his most important contribution, the Ohm's Law. The law states that 'applied voltage is directly proportional to the resultant electric current divided by the resistance of the material'.

Michael Faraday (1791 - 1867)

If it was not for Faraday, electricity would not have come to practical use. He was the one who invented electromagnetic rotary devices, and formed the foundation of electric motor technology. He was also a chemist who discovered benzene. He tried to popularize terms such as cathode, anode and electrode. Faraday explained his ideas in a clear and simple way, and is considered one of the greatest discoverers of all time.

What physics ?

What physics ?

Physics is the scientific study of matter and energy and how they interact with each other.
This energy can take the form of motion, light, electricity, radiation, gravity . . . just about anything, honestly. Physics deals with matter on scales ranging from sub-atomic particles (i.e. the particles that make up the atom and the particles that make up those particles) to stars and even entire galaxies.

How Physics Works

As an experimental science, physics utilizes the scientific method to formulate and test hypotheses that are based on observation of the natural world. The goal of physics is to use the results of these experiments to formulate scientific laws, usually expressed in the language of mathematics, which can then be used to predict other phenomena.

The Role of Physics in Science

In a broader sense, physics can be seen as the most fundamental of the natural sciences. Chemistry, for example, can be viewed as a complex application of physics, as it focuses on the interaction of energy and matter in chemical systems. We also know that biology is, at its heart, an application of chemical properties in living things, which means that it is also, ultimately, ruled by the physical laws.