physics

Karel Niessen

Karel Niessen is a physics topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Karel Niessen rather than just read about it. In short: Karel Frederik Niessen (1895 in Velsen – 1967) was a Dutch theoretical physicist who made contributions to quantum mechanics and is known for the Pauli–Niessen model. Education Niessen began his studies in physics at the University of Utrecht in 1914.

Key takeaways

Karel Niessen belongs to physics; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
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Reproduce the core statement of Karel Niessen from memory before moving on to harder problems.

Reference excerpt

Karel Frederik Niessen (1895 in Velsen – 1967) was a Dutch theoretical physicist who made contributions to quantum mechanics and is known for the Pauli–Niessen model.

Education Niessen began his studies in physics at the University of Utrecht in 1914. In 1922, he received his doctorate under L. S. Ornstein. He was an assistant at the University from 1921 to 1928, except for his postdoctoral study and research at the Ludwig-Maximilians-Universität München under Arnold Sommerfeld, 1925 to 1926 on a Rockefeller Foundation Fellowship. He also spent 1928 to 1929 on a Rockefeller Foundation Fellowship at the University of Wisconsin–Madison. In 1922, Niessen’s doctoral thesis, as well as Wolfgang Pauli’s extended doctoral thesis, dealt with the hydrogen molecule ion in the Bohr–Sommerfeld framework. Their work is referred to as the Pauli-Niessen model. Their works helped to show the inadequacy of the old quantum mechanics, which gave physicists the impetus to explore new paths which led to the matrix mechanics formulation of quantum mechanics by Werner Heisenberg and Max Born in 1925 and the wave mechanics formulation by Erwin Schrödinger in 1926, which were shown to be equivalent.

Career Upon Niessen’s return to the Netherlands in 1929, he took a lifelong position as a theoretical physicist at Philips Electronics in Eindhoven.

Selected publications Karel F. Niessen Zur Quantentheorie des Wasserstoffmolekülions, doctoral dissertation, University of Utrecht, Utrecht: I. Van Druten (1922) as cited in Mehra, Volume 5, Part 2, 2001, p. 932. K. F. Niessen Zur Quantentheorie des Wasserstoffmolekülions, Annalen der Physik 70 129-134 (1923) K. F. Niessen Ableitung des Planckschen Strahlungsgesetzes für Atome mit zwei Freiheitsgraden, Annalen der Physik 75 743–780 (1924) K. F. Niessen (Utrecht) Die Energieberechnung in einem sehr vereinfachten Vierkörperproblem, Zeitschrift für Physik Volume 43, Numbers 9-10, Pages 675-693 (1927). Received 14 April 1927. K. F. Niessen Überdie annähernden komplexen Lösungen der Schrödingerschen Differentialgleichun für den harmonischen Oszillator, Annalen der Physik 85 487-514 (1928) as cited in Jammer, 1966, p. 279. K. F. Niessen On the Saturation of the Electric and Magnetic Polarization of Gases in Quantum Mechanics, Phys. Rev. 34 253 - 278 (1929). Department of Physics, University of Wisconsin–Madison. Received 1 June 1929. K. F. Niessen (Physics Department, Madison, Wisconsin) Ein Gas in gekreuzten Feldern nach der Quantenmechanik Journal Zeitschrift für Physik, Volume 58, Numbers 1-2, Pages 63–74 (1929). Received 13 July 1929. K. F. Niessen Über das akustische analogon der sommerfeldschen oberflächenwelle Niessen, K. F. Physica 8 (3) 337-343 (1941) K. F. Niessen On one of Heisenberg's hypotheses in the theory of specific heat of superconductors, Physica 16 (2) 77-83 (1950)

References Jammer, Max The Conceptual Development of Quantum Mechanics (McGraw Hill, 1966) Mehra, Jagdish, and Helmut Rechenberg The Historical Development of Quantum Theory. Volume 5 Erwin Schrödinger and the Rise of Wave Mechanics. Part 2 The Creation of Wave Mechanics: Early Response and Applications 1925 - 1926. (Springer, 2001) ISBN 0-387-95180-6

Notes

Illustrations

Worked examples

Example 1 — a first encounter with Karel Niessen

Start with the simplest possible case. Write down what Karel Niessen claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In physics, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Karel Niessen before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Karel Niessen ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Karel Niessen

In research: Karel Niessen appears in physics research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Karel Niessen in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Karel Niessen is common in secondary-school and first-year university syllabi. It links to neighbouring topics 1895 births, 1967 deaths, 20th-century Dutch physicists, so understanding it makes those chapters shorter.
In everyday life: Look for Karel Niessen outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Karel Niessen in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Karel Niessen means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Karel Niessen out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Karel Niessen in simple terms?

Karel Frederik Niessen (1895 in Velsen – 1967) was a Dutch theoretical physicist who made contributions to quantum mechanics and is known for the Pauli–Niessen model. Education Niessen began his studies in physics at the University of Utrecht in 1914.

Why does Karel Niessen matter?

Because it connects several physics ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Karel Niessen?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Karel Niessen.