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J. D. Bernal

J. D. Bernal 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 J. D. Bernal rather than just read about it. In short: John Desmond Bernal (; 10 May 1901 – 15 September 1971) was an Irish scientist who pioneered the use of X-ray crystallography in molecular biology. He published extensively on the history of science.

J. D. Bernal — main illustration
J. D. Bernal — illustration

Key takeaways

  • J. D. Bernal belongs to physics; place it in that map before memorising details.
  • Learn the definition first, then one example that makes the definition concrete.
  • Connect J. D. Bernal to a quantity you can measure, compute or draw — that is where exam questions come from.
  • Reproduce the core statement of J. D. Bernal from memory before moving on to harder problems.

Reference excerpt

John Desmond Bernal (; 10 May 1901 – 15 September 1971) was an Irish scientist who pioneered the use of X-ray crystallography in molecular biology. He published extensively on the history of science. In addition, Bernal wrote popular books on science and society. He was a communist activist and a member of the Communist Party of Great Britain (CPGB).

Education and early life His family was Irish, with a mix of Spanish, Portuguese, Italian and Sephardic Jewish on his father's side (his grandfather Jacob Genese, properly Ginesi, had adopted the family name Bernal of his paternal grandmother around 1837). His father Samuel Bernal had been raised as a Catholic in Limerick and after graduating from Albert Agricultural College spent 14 years in Australia before returning to County Tipperary to buy a farm, Brookwatson, near Nenagh where Bernal was brought up. His American mother, née Elizabeth Miller, whose mother was from Antrim, was a graduate of Stanford University and a journalist and had converted to Catholicism. Elizabeth was raised Protestant and would send John to a Protestant school in his youth. Bernal was educated in England first for one term at Stonyhurst College, which he hated and so was moved to Bedford School at the age of 13. A pupil at the school from 1914 to 1919, according to Goldsmith he found it "extremely unpleasant" and most of his fellow students "bored him", but his younger brother Kevin, who was also there, was "some consolation", while Brown claims that "he seemed to adjust easily to life" there. In 1919, he went to Emmanuel College, Cambridge, with a scholarship. At Cambridge, Bernal read both mathematics and science for a Bachelor of Arts degree in 1922, which he followed by another year of natural sciences. He taught himself the theory of space groups, including the quaternion method, which became the mathematical basis of a lengthy paper on crystal structure for which he won a joint prize with Ronald G.W. Norrish in his third year. At Cambridge, he also became known as "Sage", a nickname given to him about 1920 by a young woman working in Charles Kay Ogden's Bookshop at the corner of Bridge Street.

Career and research After his graduation, Bernal began research under William Henry Bragg at the Davy Faraday Laboratory at the Royal Institution in London. In 1924 he determined the structure of graphite (the Bernal stacking describes the registry of two graphite planes) and also did work on the crystal structure of bronze. His strength was in analysis as much as experimental method, and his mathematical and practical treatment of determining crystal structure was widely studied, but he also developed an X-ray spectro-goniometer. In 1927, he was appointed as the first lecturer in Structural Crystallography at Cambridge, becoming the assistant director of the Cavendish Laboratory in 1934. There, he started applying his crystallographic techniques to organic molecules, starting with oestrin and sterol compounds including cholesterol in 1929, forcing a radical change of thinking among sterol chemists. While at Cambridge, he analysed vitamin B1 (1933), pepsin (1934), vitamin D2 (1935), the sterols (1936) and the tobacco mosaic virus (1937). He also worked on the structure of liquid water, showing the boomerang shape of its molecule (1933). It was in Bernal's research group that after a year working with Tiny Powell at Oxford, Dorothy Hodgkin continued her early research career. Together, in 1934, they took the first X-ray photographs of hydrated protein crystals using the trick of bathing the crystals in their mother liquor, giving one of the first glimpses of the world of molecular structure that underlies living things. Max Perutz arrived as a student from Vienna in 1936 and started the work on haemoglobin that would occupy him most of his career. However, Bernal was refused fellowships at Emmanuel and Christ's and tenure by Ernest Rutherford, who disliked him, and in 1937, Bernal became Professor of Physics at Birkbeck College, University of London, a department that had been brought to the first rank by Patrick Blackett. The same year, he was elected as a Fellow of the Royal Society. After World War II, he established Birkbeck's Biomolecular Research Laboratory in two Georgian houses in Torrington Square with 15 researchers. It was there that Aaron Klug and Rosalind Franklin worked on tobacco mosaic virus, and Andrew Donald Booth developed some of the earliest computers to help with the computation. His Guthrie lecture of 1947 concentrated on proteins as the basis of life, but it was Max Perutz, still at Cambridge, who developed the X-ray structural analysis of globular proteins in Britain. In the early 1960s, Bernal returned to the subject of the origin of life, analysing meteorites for evidence of complex molecules, and to the topic of the structure of liquids, which he talked about in his Bakerian lecture in 1962.

Ministry of Home Security In the early 1930s, Bernal had been arguing for peace, but that changed after the Spanish Civil War started. With the outbreak of World War II in 1939, Bernal joined the Ministry of Home Security, where he brought in Solly Zuckerman to carry out the first proper analyses of the effects of enemy bombing and of explosions on animals and people. Their subsequent analysis of the effects of bombs on Birmingham and Kingston upon Hull showed that city bombing produced little disruption and production was affected only by direct hits on factories. A supper for scientists organised by the Tots and Quots in Soho generated a multi-author book Science in War produced in a month by Allen Lane, one of the guests, arguing that science should be applied in every part of the war effort. From 1942, he and Zuckerman served as scientific advisers to Lord Louis Mountbatten, the Chief of Combined Operations. Bernal was able to argue on both sides of Project Habbakuk, Geoffrey Pyke's proposal to build huge aircraft landing platforms in the North Atlantic made of ice. He rescued Max Perutz from internment, getting him to perform experiments on ice related to Habbakuk in a meat store freezer below Smithfield Meat Market. This project indirectly marked his divergence from Zuckerman, when he was recalled from a joint tour of the Middle East investigating the co-operation of army and air force, but the tour established Zuckerman's reputation as a military scientist.

… excerpt ends here. Continue reading the full article.

Worked examples

Example 1 — a first encounter with J. D. Bernal

Start with the simplest possible case. Write down what J. D. Bernal 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 J. D. Bernal 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 J. D. Bernal 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 J. D. Bernal

In research
J. D. Bernal 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 J. D. Bernal 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
J. D. Bernal is common in secondary-school and first-year university syllabi. It links to neighbouring topics 1901 births, 1971 deaths, 20th-century British physicists, so understanding it makes those chapters shorter.
In everyday life
Look for J. D. Bernal 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 J. D. Bernal in 20 minutes

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

Frequently asked questions

What is J. D. Bernal in simple terms?

John Desmond Bernal (; 10 May 1901 – 15 September 1971) was an Irish scientist who pioneered the use of X-ray crystallography in molecular biology. He published extensively on the history of science.

Why does J. D. Bernal 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 J. D. Bernal?

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 J. D. Bernal.

Tags

  • 1901 births
  • 1971 deaths
  • 20th-century British physicists
  • 20th-century Irish historians
  • 20th-century science writers
  • Academics of Birkbeck, University of London
  • Alumni of Emmanuel College, Cambridge
  • British atheists
  • British biophysicists
  • British communists
  • British crystallographers
  • British fellows of the Royal Society

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