List of Danish inventions and discoveries

This is a list of Danish inventions and discoveries. The following incomplete list comprises people from Danish and of Danish origin. The following is a list of inventions or discoveries generally believed to be Danish:

Arts

• Lego — a line of plastic construction toys manufactured by the Lego Group, a privately held company based in Billund, Denmark. It was founded by Ole Kirk Christiansen, a carpenter from Billund, Denmark, who began making wooden toys in 1932. ^[1] By 1930, Christiansen employed a small workforce to maintain his growing business. ^[2]

Astronomy

• Tychonic system — a model of the universe published by Tycho Brahe in 1588, which describes the Earth as the centre of the universe, with the planets revolving around the Sun, which in turn revolves around the Earth. ^[3]

Biology

• Gram stain — a method of staining used to classify bacteria species which was developed by Danish bacteriologist Hans Christian Gram . ^{[4] [5]}
• Parotid duct — first described by Nicolas Steno.

Chemistry

• pH- The pH scale was invented in 1909 by Danish chemist Søren Peter Lauritz Sørensen at the Carlsberg Laboratory. He developed it as a convenient method for measuring the acidity or basicity of substances. ^[6]
• Hafnium – discovered by Dirk Coster and George de Hevesy in Copenhagen, 1923.

Physics

Natural physics

• Speed of light — Ole Christensen Rømer was a Danish astronomer , first demonstrated that light travels at a finite speed. ^[7]

Electrical physics

• Magnetic field — the concept that electric current creates a magnetic field was proposed by Hans Christian Ørsted. ^[8]

Quantum physics

• Bohr model — developed by Niels Bohr. ^[9]
• Bohr–Van Leeuwen theorem — proposed by Neils Bohr, it states that when statistical mechanics and classical mechanics are applied consistently, the thermal average of the magnetization is always zero. ^[10]

Technology

• Thermometer The modern thermometer, showing the temperature between two fixed points,^{[ clarification needed ]} was invented by Ole Rømer.

Computer Science

• C++ — a high-level, programming language created by Danish computer scientist Bjarne Stroustrup. ^[11]

References

1. Thorø, Marianne (2018-12-06). "LEGO-løverne har forladt Billund". Billundonline.dk - Nyheden når den er ny - fra hele Billund kommune (in Danish). Retrieved 2023-11-28.
2. Herman, Sarah (2012). Building a History: The Lego Group. Barnsley, South Yorkshire: Pen & Sword Books Ltd. Archived from the original on 27 February 2023. Retrieved 15 January 2021.
3. "The Tychonic system is, in fact, precisely equivalent mathematically to Copernicus' system." (p. 202) and "[T]he Tychonic system is transformed to the Copernican system simply by holding the sun fixed instead of the earth. The relative motions of the planets are the same in both systems ..." (p. 204), Kuhn, Thomas S. , The Copernican Revolution (Harvard University Press, 1957).
4. "Gram Stain: MedlinePlus Medical Test". medlineplus.gov.
5. Colco, R. (2005). "Gram Staining". Current Protocols in Microbiology . Appendix 3 (1): Appendix 3C. doi:10.1002/9780471729259.mca03cs00. ISBN   978-0-471-72925-9. PMID   18770544. S2CID   32452815.
6. Sørensen, S. P. L. (1909). "Über die Messung und die Bedeutung der Wasserstoffionenkonzentration bei enzymatischen Prozessen" (PDF). Biochemische Zeitschrift. 21: 131–304. Archived (PDF) from the original on 15 April 2021. Retrieved 22 March 2021. Original German: Für die Zahl p schlage ich den Namen Wasserstoffionenexponent und die Schreibweise p_H• vor. Unter dem Wasserstoffionexponenten (p_H•) einer Lösung wird dann der Briggsche Logarithmus des reziproken Wertes des auf Wasserstoffionen bezogenen Normalitätsfaktors der Lösung verstanden. Two other publications appeared in 1909, one in French and one in Danish.
7. van Helden, Albert (1983). "Roemer's Speed of Light". Journal for the History of Astronomy. 14 (2): 137–141. Bibcode:1983JHA....14..137V. doi:10.1177/002182868301400206.
8. Jacobsen, A. S.; Knudsen, O. (14 April 2021). "H.C. Ørsted". Den Store Danske (in Danish). Gyldendal. Retrieved 12 April 2023.
9. "Bohr model | Description, Hydrogen, Development, & Facts | Britannica". www.britannica.com. 2025-02-14. Retrieved 2025-02-18.
10. Alicki, Robert; Jenkins, Alejandro (2020-10-30). "Quantum Theory of Triboelectricity". Physical Review Letters. 125 (18) 186101. arXiv: 1904.11997 . Bibcode:2020PhRvL.125r6101A. doi:10.1103/PhysRevLett.125.186101. hdl:10669/82347. ISSN   0031-9007. PMID   33196235. S2CID   139102854.
11. Stroustrup, Bjarne (1997). "1". The C++ Programming Language (Third ed.). Addison-Wesley. ISBN   0-201-88954-4. OCLC   59193992.