All Thinkers

Rosalind Franklin

Rosalind Franklin (1920-1958) was a British chemist and X-ray crystallographer. She was born in London into a prominent Jewish family and showed exceptional scientific ability from childhood. She studied chemistry at Cambridge University and then worked in Paris, where she became expert in X-ray crystallography: a technique that uses X-rays to determine the three-dimensional structure of molecules. She returned to England in 1951 to work at King's College London, where she was assigned to study the structure of DNA. Working with extraordinary precision, she produced some of the clearest X-ray photographs of DNA ever taken, including the famous Photo 51, which showed clear evidence of the double-helix structure. This photograph was shown to James Watson without her knowledge or permission by her colleague Maurice Wilkins. Watson and Francis Crick, who also had access to Franklin's unpublished data through other channels, used this information to build their model of DNA. Their paper announcing the double-helix structure was published in Nature in April 1953. Franklin was not credited as a contributor. She went on to do brilliant work on the structure of viruses at Birkbeck College before dying of ovarian cancer in 1958 at the age of thirty-seven. Watson, Crick, and Wilkins received the Nobel Prize for the discovery of DNA's structure in 1962.

Origin
England, United Kingdom
Lifespan
1920-1958
Era
20th century
Subjects
Biochemistry Crystallography DNA Molecular Biology Women In Science
Skills
Scientific Thinking Research Skills Ethical Thinking Critical Thinking Health Literacy
Why They Matter

Franklin matters for two distinct but connected reasons. The first is her scientific achievement: her X-ray crystallography of DNA was technically brilliant and provided crucial evidence for the double-helix structure of DNA, one of the most important discoveries in the history of science. The second is what happened to her work: it was used without her knowledge or proper attribution to make one of the most famous scientific discoveries of the twentieth century, and she received no credit during her lifetime or in the Nobel Prize. Her story raises profound and still relevant questions about how scientific credit is allocated, how women's contributions to science have been systematically undervalued, and what structures are needed to ensure that all scientists receive fair recognition for their work. She also represents the extraordinary precision and rigour of experimental science: her crystallography was a masterwork of careful technique.

Key Ideas
1
X-ray crystallography: seeing molecules
X-ray crystallography is a technique for determining the three-dimensional structure of molecules by firing X-rays at crystallised samples and analysing the patterns of diffraction. When X-rays hit the atoms in a crystal, they are scattered in specific patterns that depend on the arrangement of the atoms. By carefully analysing these diffraction patterns, chemists can work backwards to determine the structure of the molecule. Franklin became one of the world's leading experts in this technique, capable of producing and interpreting crystallography images of extraordinary clarity and precision. It was the ideal tool for determining the structure of DNA.
2
Photo 51 and the evidence for the double helix
Photo 51 is the X-ray diffraction photograph of DNA that Franklin produced in May 1952. It showed a clear cross-shaped pattern of diffraction, which is the characteristic signature of a helical structure. The photograph also provided precise measurements of the dimensions of the helix: the spacing between the bases, the width of the helix, and the angle of the helix's twist. This information was essential for building an accurate model of DNA's structure. When Watson saw the photograph, shown to him without Franklin's knowledge, he immediately recognised its significance. He later wrote that his mouth fell open and his pulse began to race.
3
Two forms of DNA: the A and B forms
Franklin identified that DNA could exist in two distinct forms, which she called A and B, depending on the humidity of the conditions. The B form, which DNA adopts at higher humidity, was the biologically relevant form and the one that showed the clear helical structure in Photo 51. The A form was more crystalline and easier to analyse by conventional crystallography but did not show the helical structure as clearly. Franklin was methodically working through the A form when Watson and Crick, using her B-form data without her knowledge, built their famous model. This distinction between the two forms, and Franklin's recognition of which was more important, was itself a significant scientific contribution.
Key Quotations
"Science and everyday life cannot and should not be separated."
— Letter to her father, 1940
Franklin wrote this at nineteen to her father, who had questioned whether science was a suitable career for a woman. She was defending not only her choice of career but her belief that scientific knowledge was connected to the real world rather than being an abstract pursuit separate from ordinary life. This connection between science and life would characterise her approach throughout her career: she was interested in the biological structures she studied because they were the molecular foundations of living things, not because they were abstract puzzles.
"The results suggest a helical structure, which must be very closely packed, containing probably two, three, or four coaxial nucleic acid chains per helical unit."
— Unpublished MRC report, 1952
This passage from Franklin's unpublished report, which was shared with Watson and Crick without her knowledge, shows how close she was to the correct model of DNA. She had identified the helical structure, the dimensions of the helix, and the possibility of multiple strands. Her data was precise and her interpretation was careful. This passage is often cited to demonstrate that she was not, as Watson suggested, resistant to the idea of a helix: she was working towards it systematically and rigorously.
Using This Thinker in the Classroom
Scientific Thinking When introducing DNA and the techniques used to study molecular structure
How to introduce
Introduce X-ray crystallography through an analogy: if you shine light through a window screen and look at the shadow, the pattern of the shadow tells you about the structure of the screen without you having to touch it. X-ray crystallography does the same thing at the molecular level. Introduce Photo 51 and ask: what does the cross-shaped pattern tell you about DNA's structure? After discussion, introduce how Franklin produced and interpreted this image and what it revealed about the double-helix structure.
Ethical Thinking When discussing scientific ethics and credit
How to introduce
Present the situation: a scientist produces crucial data through years of careful work. Without her knowledge, a colleague shows this data to competitors who use it to make a famous discovery. She is not credited as a contributor to the discovery. Ask: is this wrong? Does the answer change depending on whether it was against the rules at the time? What rules about data sharing and credit should science have? Ask: who benefits from a system where some scientists can access others' unpublished work informally?
Further Reading

Brenda Maddox's biography Rosalind Franklin

The Dark Lady of DNA (2002, HarperCollins) is the most thorough and balanced account of her life and is written for a general audience.

For a shorter introduction

The profile of Franklin on the Profiles in Science website of the US National Library of Medicine is freely available and provides a reliable overview. The Franklin Institute in Philadelphia maintains accessible online resources about her work.

Key Ideas
1
Scientific ethics and the use of data without credit
The use of Franklin's data without her knowledge or credit raises serious questions about scientific ethics. Maurice Wilkins showed Photo 51 to James Watson without asking Franklin's permission. Max Perutz, who chaired the Medical Research Council committee to which Franklin reported, gave Watson and Crick access to her detailed unpublished data report, again without her knowledge. These actions were not illegal under the norms of science in 1953, but they would be considered serious violations of research ethics today. They illustrate how the norms governing scientific credit and data sharing can be structured in ways that disadvantage women and others outside the dominant networks.
2
The politics of scientific credit
Franklin's story illustrates how scientific credit is not simply allocated according to objective contributions but is shaped by social networks, gender norms, and institutional structures. Watson's account in The Double Helix, published in 1968, portrayed Franklin dismissively and inaccurately, and this account shaped the public understanding of her role for decades. Credit in science is partly about who controls the narrative as well as who does the work. Franklin had no opportunity to write her own account of the discovery: she died four years before Watson and Crick received the Nobel Prize, which was not awarded posthumously.
3
Work on viruses: a second brilliant career
After leaving King's College in 1953, Franklin moved to Birkbeck College, where she turned her crystallographic expertise to the study of the structure of viruses, particularly tobacco mosaic virus and polio virus. Her work in this area was widely recognised and respected by her colleagues during her lifetime and produced important findings about how viruses are assembled. This second phase of her career, though cut short by her death at thirty-seven, demonstrated that she was a scientist of exceptional ability whose contributions extended well beyond DNA. She was not simply a footnote in someone else's story.
Key Quotations
"The phosphate groups lie on the outside of the structural unit, on or near the surface of the particle."
— Unpublished MRC report, 1952
This detail from Franklin's unpublished report corrected a critical error in Watson and Crick's first attempt at building a DNA model, in which they had placed the phosphate groups on the inside of the structure. When Watson and Crick saw Franklin's data showing the phosphates were on the outside, they realised their first model was wrong. This correction was crucial to building the correct model. The use of this specific piece of Franklin's unpublished data, without her knowledge, in building the famous double-helix model is one of the clearest examples of the unacknowledged use of her work.
"I was brought up to regard science as serious, as a vocation almost."
— Attributed to Franklin
Franklin's sense of science as a vocation, a calling rather than simply a career, explains both the intensity of her commitment to her work and some of the difficulties she encountered in the competitive and often political environment of King's College. She was not interested in the social games of scientific competition: she wanted to do careful work and let the results speak for themselves. In a scientific culture that valued networking, rapid publication, and self-promotion, her approach put her at a disadvantage.
Using This Thinker in the Classroom
Cultural Heritage and Identity When examining gender and the structure of scientific recognition
How to introduce
Ask: if Franklin had been male, do students think her contributions would have been acknowledged more fully? After discussion, introduce the evidence: the sexist portrayal in Watson's book, the institutional barriers she faced, the pattern of women's contributions being attributed to male colleagues across the history of science. Ask: are these patterns purely historical, or do similar dynamics still operate in science and other professional fields? What structural changes make fair attribution of credit more likely?
Research Skills When examining how experimental technique shapes scientific discovery
How to introduce
Introduce the idea that many scientific discoveries are possible only when the right experimental technique exists. Without X-ray crystallography, the structure of DNA could not have been determined. Without Franklin's particular skill in applying the technique to DNA, Photo 51 would not have been produced. Ask: what does this tell us about the relationship between experimental technique and theoretical discovery? Connect to Nightingale: both demonstrate that careful, precise observational and experimental work is the foundation on which theoretical claims must rest.
Health Literacy When discussing why DNA structure matters for medicine
How to introduce
Connect Franklin's crystallography to contemporary medicine. The structure of DNA that her data helped reveal is the foundation for: understanding how genetic mutations cause disease, developing cancer treatments that target specific molecular structures, designing antiviral drugs, gene therapy, and genomic medicine. Ask: every time you hear about a genetic test, a targeted cancer therapy, or a vaccine designed using molecular biology, what does that have to do with Rosalind Franklin? How does foundational science connect to clinical medicine decades later?
Further Reading

For the DNA discovery controversy

Horace Freeland Judson's The Eighth Day of Creation (1979, Simon and Schuster) is the most thorough account of the molecular biology revolution and includes extensive discussion of Franklin's contributions. Anne Sayre's Rosalind Franklin and DNA (1975, Norton), written by a close friend, was the first detailed rebuttal of Watson's account.

For DNA structure and its implications

James Watson's The Double Helix (1968), while deeply problematic in its treatment of Franklin, gives a vivid account of the competitive atmosphere of the discovery.

Key Ideas
1
Gender and the structure of science
Franklin's experience was not unique: women scientists in the mid-twentieth century routinely had their contributions minimised, their access to resources restricted, and their intellectual authority questioned. At King's College she was not allowed to use the common room where male scientists had lunch. Watson's portrayal of her in The Double Helix as difficult, uncooperative, and incompetent was a caricature shaped by sexist assumptions. Her story has become important in discussions of how the structure of science, its funding, its credit systems, its social networks, and its cultural norms, can systematically disadvantage women and other groups, producing a distorted picture of who makes scientific knowledge.
2
DNA structure and its implications for biology
The double-helix structure of DNA that Franklin's data helped establish has implications that reach across all of modern biology and medicine. The complementary base-pairing of the two strands immediately suggested the mechanism by which DNA could be copied: each strand could serve as a template for a new complementary strand. The sequence of bases along the strand was the genetic code: the specific sequence of four bases encoded the information for building proteins. Understanding this structure was the foundation for the subsequent revolution in molecular biology, for the development of genetic engineering, and for the genomic medicine of the twenty-first century.
3
Rehabilitation and recognition
The rehabilitation of Franklin's reputation began with Anne Sayre's biography Rosalind Franklin and DNA (1975), which challenged Watson's account and presented her contributions accurately. Since then, her story has become widely known and her contributions are now acknowledged in most accounts of the discovery of DNA's structure. The question of whether she would have shared the Nobel Prize had she lived is debated: the prize is sometimes awarded to more than three people in a discovery, but there is no way of knowing how the committee would have decided. Her story continues to be taught in science education as an example of how gender bias can affect the production and recognition of scientific knowledge.
Key Quotations
"In my view, all that is necessary for faith is the belief that by doing our best we shall come nearer to success and that success in our aims is worth having."
— Letter to her father, 1940
Franklin wrote this in the same letter as her statement about science and everyday life, and it reveals her secular but deeply committed worldview. She did not frame her commitment to science in religious terms but in terms of effort and purpose: if you work as well as you can, you will move closer to truth, and moving closer to truth is worthwhile. This is a statement about the intrinsic value of intellectual work and the possibility of genuine progress, written by someone who had not yet begun her greatest achievements.
"We wish to suggest a structure for the salt of deoxyribose nucleic acid. This structure has novel features which are of considerable biological interest."
— Watson and Crick, Nature, 1953 — the paper that used Franklin's data without credit
This is the opening of Watson and Crick's famous 1953 paper announcing the double-helix structure. The paper acknowledged Franklin and Wilkins only with a footnote stating that they had been stimulated by general knowledge of unpublished experimental results from King's College. The extent to which Watson and Crick had used specific data from Franklin's unpublished report, rather than just general knowledge, was not disclosed in the paper and was not publicly known until decades later. Including this quotation in the context of Franklin's profile makes visible the gap between the paper's acknowledgment and the actual use of her work.
Using This Thinker in the Classroom
Critical Thinking When examining contested historical narratives
How to introduce
Present the two accounts: Watson's account in The Double Helix, and the account that emerged from later historical research. Ask: why were these accounts so different? What motivated Watson's portrayal of Franklin? How do historians evaluate competing accounts of the same events? Connect to Ibn Khaldun's critical historiography: the historian must examine the social conditions and interests that shaped each account rather than simply accepting the one that was published first or told most vividly.
Global Studies When examining who produces scientific knowledge and who gets credit
How to introduce
Extend the Franklin discussion to the broader question of whose contributions to science are recognised and whose are not. Franklin is one of the most prominent examples but not the only one: women, scientists from non-Western countries, and scientists working in institutions outside the main scientific centres have all historically been underrepresented in the attribution of scientific credit. Ask: does this matter for science itself, or only for the individuals involved? If certain perspectives and approaches are systematically excluded from recognition, what might be missed?
Common Misconceptions
Common misconception

Franklin discovered DNA.

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What to teach instead

DNA was discovered long before Franklin: Friedrich Miescher first isolated it in 1869. Franklin's contribution was to produce crucial X-ray crystallographic evidence for the three-dimensional structure of DNA, particularly its double-helix form. She did not discover DNA; she helped determine its shape. This distinction matters because the structure of DNA, rather than its existence, was what explained how genetic information could be copied and transmitted.

Common misconception

Watson and Crick stole Franklin's discovery.

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What to teach instead

The situation is more complex than theft. Watson and Crick were working independently on DNA structure using published information and model-building. They were shown Franklin's Photo 51 by Wilkins without her knowledge, and they had access to her unpublished data report through Perutz. This access significantly accelerated their work and corrected an error in their model. Whether this constitutes theft depends on the norms one applies: under contemporary research ethics it would be considered a serious violation; under the norms of 1953 it was in a grey area. The clearest wrong was the failure to credit her adequately in the published paper and the subsequent misrepresentation of her role.

Common misconception

Franklin was close to the correct structure but refused to accept the helix model.

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What to teach instead

Watson's portrayal of Franklin as hostile to the helix idea was inaccurate and shaped by his own biases. Franklin's unpublished data and notes show that she had identified the helical structure of B-form DNA and was working towards a correct model. She was being methodical, preferring to work through the more tractable A-form before making claims about the B-form. This methodical approach was scientifically sound but slower than Watson and Crick's model-building approach, which relied partly on her unpublished data.

Common misconception

If Franklin had lived she would definitely have received the Nobel Prize.

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What to teach instead

The Nobel Prize is not awarded posthumously, so Franklin was ineligible when the prize was awarded to Watson, Crick, and Wilkins in 1962. Whether she would have been included had she lived is genuinely uncertain. Nobel Prizes in science are limited to three recipients, and there were already three male scientists receiving the 1962 prize. Some argue that her contributions were significant enough to warrant inclusion; others argue that the prize correctly recognises Watson, Crick, and Wilkins as the primary architects of the model. The question is impossible to answer but worth raising because it reveals how the structure of prizes and recognition systems shapes whose contributions are acknowledged.

Intellectual Connections
Complements
Gregor Mendel
Mendel established the laws of inheritance through mathematical analysis of observable traits. Franklin helped determine the physical structure of the molecule that carries the information those laws describe. Together they represent two levels of the same phenomenon: Mendel at the level of observable inheritance patterns, Franklin at the level of molecular structure. The connection between these levels, understanding how the double-helix structure of DNA implements Mendel's laws, is one of the great achievements of twentieth-century biology.
In Dialogue With
Marie Curie
Both Franklin and Curie were women scientists who made foundational contributions to their fields and whose contributions were shaped and sometimes obscured by the gender structures of the scientific world they worked in. Both worked with radiation-related techniques. Both died young of cancers that may have been connected to their work. Both have become iconic figures whose stories are used to discuss the treatment of women in science and the conditions necessary for all scientists to do their best work.
In Dialogue With
Florence Nightingale
Both Franklin and Nightingale were women whose precise, careful empirical work was essential to major advances in their fields, and both faced institutional structures that restricted what they could do and limited how they were recognised. Both have been retrospectively recognised as more important than contemporary accounts suggested. Both also demonstrate the foundational importance of careful observational and experimental work: Nightingale's meticulous data collection and Franklin's precise crystallography are both examples of the rigour that underlies scientific progress.
In Dialogue With
Simone de Beauvoir
De Beauvoir's analysis of how women are defined as the Other in a male-centred world is directly applicable to Franklin's experience in science. Watson's portrayal of her as difficult and uncooperative, his focus on her appearance and manner, his difficulty accepting her as an intellectual equal, all reflect the arrogant perception that Lugones analysed: seeing another person through your own categories rather than as they actually are. De Beauvoir's framework explains not only what happened to Franklin but why it was so difficult for her contemporaries to see it clearly.
In Dialogue With
Thomas Kuhn
Franklin's story illustrates important aspects of Kuhn's analysis of how science actually works. The race to determine DNA's structure was not a pure exercise in rational inquiry: it involved access to unpublished data, institutional networks that were differentially available to different scientists, and social dynamics that shaped who had access to what information. Kuhn's argument that science is a social activity shaped by paradigms, communities, and human factors as well as by evidence is illustrated vividly by the history of the DNA discovery.
In Dialogue With
Paul Farmer
Franklin's crystallographic work on the structure of viruses, particularly tobacco mosaic virus and polio virus, was directly connected to understanding the biological basis of the infectious diseases that Farmer worked to treat. Understanding how viruses are assembled at the molecular level is foundational to developing antiviral treatments and vaccines. Franklin's work on virus structure, less famous than her DNA work but highly respected by her contemporaries, contributed to the molecular biology of infectious disease.
Further Reading

For the technical crystallography

Franklin's original papers in Acta Crystallographica and Nature are available through academic libraries. For gender in the history of science: Londa Schiebinger's The Mind Has No Sex? Women in the Origins of Modern Science (1989, Harvard University Press) provides the historical context for understanding Franklin's experience.

For the contemporary debate about attribution

The letter published in Nature in 2023 by historians of science arguing for a reassessment of the DNA discovery is freely available and represents current scholarly thinking.