Wilhelm Carl Werner Otto Fritz Franz Wien (German: [ˈvɪlhɛlm ˈviːn]; 13 January 1864 – 30 August 1928) was a German physicist who studied heat and electromagnetism. He discovered a rule called Wien's displacement law, which helps calculate how much energy a blackbody emits at any temperature based on its emission at a known temperature.

He also created a formula that accurately describes how black-body radiation behaves when light acts like a gas of particles. His work used a concept called adiabatic invariance, which helped scientists develop the field of quantum mechanics. Wien was awarded the Nobel Prize in Physics in 1911 for his research on heat radiation.

He was related to Max Wien, who invented the Wien bridge.

Biography

Wien was born in Gaffken (now in Baltiysky District) near Fischhausen in the Province of Prussia as the son of landowner Carl Wien. In 1866, his family moved to Drachenstein near Rastenburg (now Kętrzyn, Poland).

In 1879, Wien attended school in Rastenburg. From 1880 to 1882, he studied at the city school in Heidelberg. In 1882, he enrolled at the University of Göttingen and the University of Berlin. From 1883 to 1885, he worked in the laboratory of Hermann von Helmholtz. In 1886, he earned his Ph.D. with a thesis about how light bends when it hits metals and how different materials affect the color of light that is bent. From 1896 to 1899, Wien taught at RWTH Aachen University. He became the successor of Wilhelm Conrad Röntgen twice: in 1900 at the University of Würzburg and in 1920 at the University of Munich. Wien was active in science politics and supported conservative and nationalistic ideas, but he was not as extreme as those who promoted "Deutsche Physik." He respected Albert Einstein and the theory of relativity.

In 1896, Wien found a rule for how heat energy is spread in blackbody radiation, which later became known as Wien's law. Max Planck, a colleague of Wien, did not believe in rules based on experiments. Instead, he used electricity and heat to create a theory that explained Wien's law, which became the Wien–Planck law. However, Wien's law only worked for high-frequency radiation and did not correctly predict the energy at low frequencies. Planck improved the theory and created what is now called Planck's law, which helped develop quantum theory. Wien's other rule, λ max T = constant, which shows how the peak wavelength of light from a hot object relates to its temperature, is still used today. In 1900, after studying the work of George Frederick Charles Searle, Wien proposed that all matter has electromagnetic mass and created the formula m = (4/3)E/c² to describe how electromagnetic energy relates to mass.

Wien invented the Wien filter (also called a velocity selector) in 1898 to study anode rays. This device uses electric and magnetic fields that are at right angles to each other. It can be used to separate charged particles based on their speed, such as in electron microscopes and spectrometers. It is also used in accelerator mass spectrometry to select particles with specific speeds. The device allows particles moving at the correct speed to pass through without being affected, while other particles are deflected. It can be used as a tool to measure the energy, color, or mass of particles.

While studying streams of ionized gas, Wien discovered a particle in 1898 that had the same mass as a hydrogen atom. This work helped create the field of mass spectrometry. J. J. Thomson improved Wien's equipment and did more experiments in 1913. Later, after research by Ernest Rutherford in 1919, Wien's particle was named the proton.

In 1911, Wien was awarded the Nobel Prize in Physics for his discoveries about the rules that govern heat radiation. He gave the Ernest Kempton Adams Lecture at Columbia University in 1913.

Publications

• —— (1898). "Ueber die Fragen, welche die translatorische Bewegung des Lichtäthers betreffen." Annalen der Physik. 301 (3): 1–18. Bibcode: 1898AnP…301….1D. doi: 10.1002/andp.18983010502.
• —— (1900). Lehrbuch der Hydrodynamik. S. Hirzel. ISBN 978-0-691-21419-1. OCLC 557663670. OL 16968004M. {{cite book}}: ISBN / Date incompatibility (help).
• —— (1900). "Über die Möglichkeit einer elektromagnetischen Begründung der Mechanik." Annalen der Physik. 310 (7): 501–513. Bibcode: 1901AnP…310..501W. doi: 10.1002/andp.19013100703.
• —— (1904a). "Über die Differentialgleichungen der Elektrodynamik für bewegte Körper. I." Annalen der Physik. 318 (4): 641–662. Bibcode: 1904AnP…318..641W. doi: 10.1002/andp.18943180402.
• —— (1904b). "Über die Differentialgleichungen der Elektrodynamik für bewegte Körper. II." Annalen der Physik. 318 (4): 663–668. Bibcode: 1904AnP…318..663W. doi: 10.1002/andp.18943180403.
• —— (1904c). "Erwiderung auf die Kritik des Hrn. M. Abraham." Annalen der Physik. 319 (8): 635–637. Bibcode: 1904AnP…319..635W. doi: 10.1002/andp.19043190817.
• —— (1904d). "Zur Elektronentheorie." Physikalische Zeitschrift. 5 (14): 393–395.
• —— (1930). Aus dem Leben und Wirken eines Physikers. Johann Ambrosius Barth. ISBN 978-0-691-21419-1. OCLC 249831418. {{cite book}}: ISBN / Date incompatibility (help).
• —— (1913). Neuere Probleme der theoretischen Physik (in German). B. G. Teubner. LCCN 14005571. OL 6565621M.