Julius Johann Phillipp Ludwig Elster (24 December 1854 in Blankenburg – 6 April 1920) was a teacher and physicist.

Biography

Elster and

Hans Friedrich Geitel Hans Friedrich Karl Geitel (16 July 1855 in Braunschweig – 15 August 1923 in Wolfenbüttel) was a German physicist. He is credited with coining the phrase "atomic energy." Biography Through the relocation of his family, his father was a foreste ...

, the son of a Forstmeister who had moved to

Blankenburg Blankenburg may refer to: Places * Blankenburg am Harz, a German town in the district of Harz, Saxony-Anhalt * Blankenburg Castle (Harz), the castle in Blankenburg am Harz (see above) * Bad Blankenburg, a German town in the Saalfeld-Rudolstadt dis ...

with his family in 1861, grew up in the same neighborhood and attended school and high school together. The personal friendship was deepened by the shared interest in the

natural science Natural science is one of the branches of science concerned with the description, understanding and prediction of natural phenomena, based on empirical evidence from observation and experimentation. Mechanisms such as peer review and repeatab ...

s during their years at university in

Heidelberg Heidelberg (; Palatine German language, Palatine German: ''Heidlberg'') is a city in the States of Germany, German state of Baden-Württemberg, situated on the river Neckar in south-west Germany. As of the 2016 census, its population was 159,914 ...

and

Berlin Berlin ( , ) is the capital and largest city of Germany by both area and population. Its 3.7 million inhabitants make it the European Union's most populous city, according to population within city limits. One of Germany's sixteen constitue ...

. After they received their

teaching certification A certified teacher is an educator who has earned credentials from an authoritative source, such as the government, a higher education institution or a private body or source. This teacher qualification gives a teacher authorization to teach and ...

in Brunswick, they went their separate ways for a short time. In 1881 they were working together at the ''Herzogliche Große Schule'' (translation: Ducal Great School) in

Wolfenbüttel Wolfenbüttel (; nds, Wulfenbüddel) is a town in Lower Saxony, Germany, the administrative capital of Wolfenbüttel District. It is best known as the location of the internationally renowned Herzog August Library and for having the largest c ...

and used their leisure for

experimental research An experiment is a procedure carried out to support or refute a hypothesis, or determine the efficacy or likelihood of something previously untried. Experiments provide insight into cause-and-effect by demonstrating what outcome occurs when a ...

. There Karl Bergwitz (1875–1958) was among their students. Elster was awarded an

honorary doctorate An honorary degree is an academic degree for which a university (or other degree-awarding institution) has waived all of the usual requirements. It is also known by the Latin phrases ''honoris causa'' ("for the sake of the honour") or ''ad hon ...

(1915) along with Geitel at the

Braunschweig University of Technology Braunschweig () or Brunswick ( , from Low German ''Brunswiek'' , Braunschweig dialect: ''Bronswiek'') is a city in Lower Saxony, Germany, north of the Harz Mountains at the farthest navigable point of the river Oker, which connects it to the No ...

. In 1919, he was diagnosed with

diabetes mellitus Diabetes, also known as diabetes mellitus, is a group of metabolic disorders characterized by a high blood sugar level ( hyperglycemia) over a prolonged period of time. Symptoms often include frequent urination, increased thirst and increased ap ...

. In April 1920, the Privy Councilor Julius Elster died in Bad Harzburg during a spa stay.

Publications

Together with his friend Hans Geitel, he has well over 100 publications on

atmospheric electricity Atmospheric electricity is the study of electrical charges in the Earth's atmosphere (or that of another planet). The movement of charge between the Earth's surface, the atmosphere, and the ionosphere is known as the global atmospheric electr ...

, the intensity of the

starlight Starlight is the light emitted by stars. It typically refers to visible electromagnetic radiation from stars other than the Sun, observable from Earth at night, although a component of starlight is observable from Earth during daytime. Sunligh ...

, ihe problems of

ionizing radiation Ionizing radiation (or ionising radiation), including nuclear radiation, consists of subatomic particles or electromagnetic waves that have sufficient energy to ionize atoms or molecules by detaching electrons from them. Some particles can travel ...

(example: "''On the radioactivity of the earth substrate and its possible relationship to the geothermal''") and other important areas of research a valuable contribution paid to the development of physics. Together with Geitel Julius Elster invented a modern

photoelectric cell A solar cell, or photovoltaic cell, is an electronic device that converts the energy of light directly into electricity by the photovoltaic effect, which is a physical and chemical phenomenon.

References

;Literature * Rudolf G. A. Fricke: J. Elster & H. Geitel. Jugendfreunde, Gymnasiallehrer, Wissenschaftler aus Passion. Döring Druck, Braunschweig, 1992, . * Rudolf E. Ottmer: Elster, Julius. In:

Neue Deutsche Biographie ''Neue Deutsche Biographie'' (''NDB''; literally ''New German Biography'') is a biographical reference work. It is the successor to the ''Allgemeine Deutsche Biographie'' (ADB, Universal German Biography). The 26 volumes published thus far cover ...

(NDB). Volume 4, Duncker & Humblot, Berlin, 1959, , pp. 468 f. {{DEFAULTSORT:Elster, Julius 1854 births 1920 deaths People from Blankenburg (Harz) People from the Duchy of Brunswick 20th-century German physicists 19th-century German physicists