Heinrich Friedrich Emil Lenz (February 12, 1804 – February 10, 1865) was a Russian
physicistA physicist is a scientist who studies or practices physics. Physicists study a wide range of physical phenomena in many branches of physics spanning all length scales: from sub-atomic particles of which all ordinary matter is made to the behavior of the material Universe as a whole...
of Baltic German ethnicity. He is most noted for formulating
Lenz's lawLenz's law is a common way of understanding how electromagnetic circuits must always obey Newton's third law and The Law of Conservation of Energy...
in electrodynamics in 1833.
Lenz was born in
DorpatTartu is the second largest city of Estonia. In contrast to Estonia's political and financial capital Tallinn, Tartu is often considered the intellectual and cultural hub, especially since it is home to Estonia's oldest and most renowned university. Situated 186 km southeast of Tallinn, the...
(now Tartu, Estonia), the Governorate of Livonia, in the
Russian EmpireThe Russian Empire was a state that existed from 1721 until the Russian Revolution of 1917. It was the successor to the Tsardom of Russia and the predecessor of the Soviet Union...
at that time. After completing his secondary education in 1820, Lenz studied chemistry and physics at the
University of DorpatThe University of Tartu is a classical university in the city of Tartu, Estonia. University of Tartu is the national university of Estonia; it is the biggest and highest-ranked university in Estonia...
. He traveled with the navigator
Otto von KotzebueOtto von Kotzebue was a Baltic German navigator in Russian service....
on his third expedition around the world from 1823 to 1826. On the voyage Lenz studied climatic conditions and the physical properties of
seawaterSeawater is water from a sea or ocean. On average, seawater in the world's oceans has a salinity of about 3.5% . This means that every kilogram of seawater has approximately of dissolved salts . The average density of seawater at the ocean surface is 1.025 g/ml...
. The results have been published in "Memoirs of the St. Petersburg Academy of Sciences" (1831).
After the voyage, Lenz began working at the University of St. Petersburg, Russia, where he later served as the Dean of Mathematics and Physics from 1840 to 1863 and was
RectorThe word rector has a number of different meanings; it is widely used to refer to an academic, religious or political administrator...
from 1863 until his death in 1865. Lenz also taught at the Petrischule in 1830 and 1831, and at the Mikhailovskaya Artillery Academy.
Lenz had begun studying
electromagnetismElectromagnetism is one of the four fundamental interactions in nature. The other three are the strong interaction, the weak interaction and gravitation...
in 1831. Besides the law named in his honor, Lenz also independently discovered
Joule's lawJoule's laws are a pair of laws concerning the heat produced by a current and the energy dependence of an ideal gas to that of pressure, volume, and temperature, respectively...
in 1842; to honor his efforts on the problem, it is also given the name the "Joule–Lenz law," named also for
James Prescott JouleJames Prescott Joule FRS was an English physicist and brewer, born in Salford, Lancashire. Joule studied the nature of heat, and discovered its relationship to mechanical work . This led to the theory of conservation of energy, which led to the development of the first law of thermodynamics. The...
.
Lenz eagerly participated in development of the
electroplatingElectroplating is a plating process in which metal ions in a solution are moved by an electric field to coat an electrode. The process uses electrical current to reduce cations of a desired material from a solution and coat a conductive object with a thin layer of the material, such as a metal...
technology, invented by his friend and colleague
Moritz von Jacobi. In 1839 Lenz produced several medallions using
electrotypingElectrotyping is a chemical method for forming metal parts that exactly reproduce a model. The method was invented by Moritz von Jacobi in Russia in 1838, and was immediately adopted for applications in printing and several other fields...
. Along with the electrotyped relief produced by Jacobi the same year, these were the first instances of galvanoplastic sculpture.
Lenz died in Rome, Italy, after suffering from a stroke.
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