JAMES PRESCOTT  JOULE

          James Prescott Joule, an English Physicist, was born in Salford, near Manchester, England, on December 24, 1818. He was the second of five children born to a wealthy brewery owner.

     Joule studied the nature of heat and discovered its relationship to mechanical work. In his time, Joule is best known for his research in electricity and thermodynamics. He worked with Lord Kelvin (William Thomson, Irish physicist) to develop the absolute scale of temperature, made observations on magnetostriction, and found the relationship between the current through a resistance and the heat dissipated, now called Joule’s Law.

Joule experimentally verified the law of conservation of energy in his study of the transfer of mechanical energy into heat energy. Using many independent methods, Joule determined the numerical relation between heat and mechanical energy, or the mechanical equivalent of heat .

Joule found that the temperature of a gas falls when it expands without doing any work. This principle, which became known as the Joule-Thomson effect, underlies the operation of common refrigeration and air conditioning systems.

Joule died  in Sale in 1889 and buried in Brooklands cemetery there.

1850- Fellow of the  Royal Society

1852– Royal Medal

1860– President of Manchester Literary and Phisolophical Society

1872-1887 President of the British Association for the Advancement of Science       

Works of James Prescott Joule

1838   He  discovered an electromagnetic motor.
1840  He discovered Joule’s Law.

 1843 He calculated the amount of mechanical work needed to produce an equivalent amount of heat. This quantity was called ‘the mechanical equivalent of heat’.

 1846 He discovered that an iron bar fractionally changed its length when magnetized, later it was called as “magnetostriction”.

 1848 He published “Kinetic Theory of Gas”.

1852-1856 He discovered that temperature of a gas falls when it expans without doing work, with William Thomson known as “ Joule-Thomson Effect” and underlies the operation of common refrigeration and air-conditioning systems.

 1863- He draw the magnification of sketch  in his letter to William Thomson.

Areas of  Joule’s Law in our daily lives

   In our daily lives, most of electrical    equipments such as, irons, heaters, kettles and coffee machines operate according to Joule’s Law principle
   Kinetic theory is one of the most important method for the scientist in order to study on gas, especially to observe the behaviors of gas.         Magnetostriction  is also used for  making ultra-sonic .         In the modern SI system, the energy needed to raise the temperature of 1 kg of water by one degree kelvin is 4,184 J kg-1 K-1 and this is called the specific heat capacity of water.To produce energy in atomic power station by using the avaerage speed of gas.

Michael Faraday

Michael Faraday (22 September 1791 – 25 August 1867) was an English chemist and physicist who contributed greatly to the fields of electromagnetism and electrochemistry

He began his career as a chemist and became one of the greatest scientists of the 19^th century.

He discovered a number of new organic compounds such as benzene, the first to liquefy a permanent gas. His major contribution was in the field of electricity and magnetism. He was the first to produce an electric current from a magnetic field, invented the first electric motor and dynamo, demonstrated the relation between electricity and chemical bonding, discovered the effect of magnetism on light, and discovered and named diamagnetism, the peculiar behavior of certain substances in strong magnetic fields. Also he introduced several words that we still use today to discuss electricity such as ion, electrode, electrolysis, cathode and anode.

 Using old bottles and lumber, he made a crude electrostatic generator and did simple experiments. He also built a weak voltaic pile with which he performed experiments in electrochemistry.

 During his lifetime, Faraday rejected a knighthood and twice refused to become President of the Royal Society. Faraday was one of eight foreign members elected to the French Academy of Sciences in 1844.

 In 1848, as a result of representations by the Prince Consort, Michael Faraday was awarded a grace and favour house in Hampton Court, Surrey free of all expenses or upkeep. This was the Master Mason's House, later called Faraday House, and now No.37 Hampton Court Road. In 1858 Faraday retired to live there. Also he died at his house at Hampton Court on 25 August 1867.

 Works of Michael Faraday:

• 1839-1855 Experimental Researches in Electricity
• 1850 Experimental Researches in Chemistry and Physics
• 1831 Michael Faraday discovered the principle of elektromagnetic induction, Faraday’s Law and did the first experiments with induction between coils of wire.

 Magnetic field lines were introduced by Michael Faraday.

 Several expressions that we still use today to discuss electricity such as ion, electrode, electrolysis, cathode and anode were discovered by Michael Faraday.

 Places of the electrolysis usage in our daily lives

 Electrolysis is used especially in metallurgy with electrolysis, preparation of metals or purifying of it. Also, it is used in electroplating, casting mold with metal accumulation and protection against corrosion. In addition to that it is one of the methods for metals plating with an accumulation of metal, for instance; nickel plating, zinc plating, calcium plating, chlorine plating, silver or gold plating.

 Gas production (chlorine), obtaining of protective oxide anode layer on the metal ( process of aluminium  to be an anode via an alumina), polishing with electrolysis, purifying metals from oils as cathode or anode are also included in the application of electrolysis.