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20th Century Scientific Developments

Page history last edited by Robert W. Maloy 2 years, 1 month ago


"Berlin to New York in less than One Hour!" November 1931 Magazine Cover




Focus Question: What were the social and political impacts of work of Einstein, Fermi, Oppenheimer, the other atomic scientists, von Braun, Salk, and Watson and Crick as well as women and scientists of color?


Topics on the Page


Albert Einstein and the Theory of Relativity

    • Mileva Maric


Enrico Fermi, J. Robert Oppenheimer, Edward Teller, and nuclear energy

Wernher von Braun and space exploration

Jonas Salk and the polio vaccine

James Watson, Francis Crick, the discovery of DNA, and the Human Genome Project


Female Scientists in U.S. and World History










Scientists of Color

LGBTQ History and Scientists






Albert Einstein and the Theory of Relativity

See The Collected Papers of Albert Einstein from Princeton University.

Albert Einstein: Life Timeline


Einstein in 1921
Einstein in 1921

external image Relativity-formula.png

  • In the beginning of the 20th century, a young Swiss clerk named Albert Einstein (1879-1955) published the theory of relativity


  • The theory of relativity is the most successful development in the history of science in terms of its coherence with experimental results and its ability to foretell new phenomena.


  • Einstein's theory immediately explained some of the major problems in the fields of physics and astronomy of his day


  • It has continued to clarify new information that were not even hinted at 90 years ago including the existence of black holes and recent observations in cosmology.


  • Accepting the theory of relativity requires us to forget almost all of our previous opinions about the universe as well as most of what we would call common sense.


  • Space and time, which to humans locked on planet Earth seems rather uniform, seem to be unchanging with regards to the events of the Cosmos.


  • The famous equation, E = mc2, in suggesting an equivalence between energy and mass, meaning that a great amount of energy could come from a small amount of mass, laid the groundwork for the future of nuclear power.


For more about the Einstein and his Theory of Relativity, see Einstein's Theory of Relativity.

  • Einstein was impacted by and involved in political developments around in the world.


  • A lifelong resident of Germany, Einstein decided to remain in the United States while on tour there in 1933 due to the rise to power of Adolf Hitler and the Nazi Party.
    • Einstein came from a Jewish family background, which made his continued presence in Germany potentially very dangerous.


  • Einstein would live the rest of his life in the United States, eventually becoming a U.S. citizen in 1940.


  • In 1939 Einstein wrote a famed letter (see below) to President Franklin Roosevelt warning about the potential German development of atomic weapons.
    • This helped lead to the Manhattan Project and eventual development of the American atomic bomb.
    • Despite this, Einstein later became vehemently opposed to the use and stockpiling of nuclear weapons.
    • Along with the British philosopher Bertrand Russell, Einstein sponsored the 1955 Russell-Einstein Manifesto (see below) urging nations to seek peaceful solutions to international conflicts

Mileva Maric, 1896
external image Red_apple.jpgAnimated Video: Einstein's Theory of Relativity: An animated video explaining General Relativity


Photograph of Mileva Maric, 1896


Lesson plan idea would be to learn about Mileva Maric Einstein, Albert Einstein's wife, and her role in her husband's success, and use her life as a "metaphor for the struggle and prejudice that women in science encountered well into the 20th century."



Enrico Fermi, J. Robert Oppenheimer, Edward Teller – Nuclear Energy


Teller in 1958
Teller in 1958


  • Fermi, Oppenheimer, and Teller were three of the most prominent scientists involved in the development of the nuclear bomb and nuclear energy.


  • The three of them all worked in some aspects of the American Manhattan Project to develop an atomic bomb.


  • Despite their joint work, the three all made significant independent contributions and often differed in their views on the appropriate applications of their research.


  • The development of the Hydrogen bomb led to an arms race with the Soviet Union, one that would last for decades.


  • After World War II and the bombings of Hiroshima and Nagasaki, The United States and the Soviet Union became the two dominant political powers in the world.
    • This mostly had to do with the development of Nuclear weapons, but also had to do with the fact that Europe had been decimated by the war.


  • Eventually, more and more countries began to develop nuclear technology bringing them tremendous power within the realm of global affairs.
    • Current countries with nuclear weapons: United States, Russia, the United Kingdom, France, India, Israel, China, North Korea, and Pakistan. [2]

external image 200px-Hebrew_timeline.svg.pngTimeline of the Hydrogen Bomb

Fermi in the 1940's
Fermi in the 1940's

Enrico Fermi (1901-1954)

  • an Italian-born physicist
  • left Italy for the United States in 1938 due to the influence of the Fascist regime of Benito Mussolini (similar to Albert Einstein's leaving Germany five years earlier).
  • Fermi was already a prominent physicist in Italy prior to arriving in America
    • known for uniquely specializing in both theoretical and experimental physics.
  • Once in the United States, Fermi immediately played a large role in the Manhattan Project, helping to design the first ever artificial nuclear reactor (Chicago Pile 1)
  • He was on hand for the 1945 "Trinity Test", the first ever detonation of an atomic bomb near Alamogordo, New Mexico.
  • In physics, engineering, and mathematics he is famous for the "Fermi Method", a process of accurately estimating from very limited information.
  • Fermi later became an active opponent to the development of hydrogen and nuclear weapons.
    • In 1949 he publicly opposed the proposal to develop the first hydrogen bomb, though it was eventually built anyway.
  • In 1954 he testified on behalf of maintaining Robert Oppenheimer's U.S. security clearance.
  • He died later in 1954 of stomach cancer at the age of 53.
  • See more about Fermi here, from the University of Chicago library which has pictures, a biography, and PDF of his notes.


Watch Fermi and his assistants reenact experiments at the site of Chicago Pile-1, nuclear reactor.

J. Robert Oppenheimer (1904-1967)

  • The man today probably most associated with the Manhattan Project and the development of the atomic bomb.
  • Before the Project, Oppenheimer was a prominent physics professor at the University of California, Berkeley.
    Oppenheimer in 1946
    Oppenheimer in 1946


  • He was known for his research in theoretical astronomy and astrophysics
    • his often diverse and wide-ranging academic interests which extended well beyond his professional research.


  • He was contacted by Leslie Groves, director of what became the Manhattan Project, to take part in the project and immediately became one of its most indispensable contributors. 


  • He later became the primary engineer of the Trinity Test (at which Fermi was also present), the first ever detonation of a nuclear bomb.
    • After this, he famously quoted from the sacred Indian text the Bhagavad Gita, saying "Now I am become Death, the destroyer of worlds."


J. Robert Oppenheimer, November 8, 1948 cover of Time magazine


J. Robert Oppenheimer on the November 8, 1948 cover of Time magazine.

  • After the atomic bombs were used by the United States to bomb the Japanese cities of Hiroshima and Nagasaki, the public became aware of the work of the Manhattan Project scientists.


  • Oppenheimer became the most visible public spokesman for the project, by extension perhaps all of science
      • he appeared on multiple covers of Time magazine


  • His very visible public persona led to continued questions from the power and authority of government about his political opinions and background.


  • In particular, he caught the attention of J. Edgar Hoover, powerful director of the FBI.


  • Investigations into his past left-wing leanings and possible Communist Party affiliations led to the revulsion of his national security clearance in 1954.


  • The hearings surrounding Oppenheimer's security clearance became highly public and controversial.
    • Most academics, including Fermi, testified on his behalf, but Edward Teller was among those testifying against him.


  • In the aftermath of the hearings, Oppenheimer no longer held an official government position but remained in the public eye.


  • He became a powerful public advocate on both the importance and potential dangers of science, and also spoke against the potential use of nuclear weapons, and about the extreme danger these weapons posed to the planet.


  • He died of cancer in 1967 at the age of 62.

external image Essener_Feder_01.pngTranscript of 1954 Oppenheimer Security Hearing

external image Red_apple.jpg



  • This site offers a teacher's guide companion to PBS' American Experience episode, "The Trials of J. Robert Oppenheimer." You can also watch the entire episode online.

Edward Teller (1908-2003)

Teller, Los Alamos, WWII badge photo
Teller, Los Alamos, WWII badge photo


  • prominent foreign-born physicist who moved to the United States to work on the Manhattan Project.
  • He was born in Hungary, and moved to the United States in the 1930s.
  • He extended some of the earlier discoveries of Enrico Fermi to discover some of the great potential in atomic and nuclear energy.
  • After helping the Manhattan Project develop the atomic bomb, Teller was enthusiastic about the development of even more powerful weapons
    • such as the hydrogen and nuclear bombs.
    • also strongly pushed for the development of nuclear power and nuclear energy (distinct from nuclear weapons), which is still very controversial today.
  • His weapons development advocacy put him at odds with other prominent scientists like Fermi and Oppenheimer.
  • Not satisfied with mere atomic weapons capabilities, Teller decided to push technology further and started the project on nuclear energy.
  • At times, Teller and Oppenheimer would be at odds
    • the eventual project would lead to the production and successful testing of the Hydrogen Bomb.
  • Teller testified against Oppenheimer in the 1954 hearings, saying
    • "I thoroughly disagreed with him in numerous issues and his actions frankly appeared to me confused and complicated. To this extent I feel that I would like to see the vital interests of this country in hands which I understand better, and therefore trust more." (see transcript below).
  • His statements against Oppenheimer were not well regarded in the academic community
    • He continued to find support from the government and military establishment for various projects throughout the rest of his life.

external image Red_apple.jpgEdward Teller Interview 1970s interview with Edward Teller about nuclear energy

 Wernher von Braun - Space Exploration

Wernher von Braun (1912-1977)

  • He was one of the most significant rocket developers and crucial components of space exploration, during the period between the 1930s and the 1970s.
  • As a young man he became infatuated with the possibilities of space exploration by reading many science fiction novels
    • They prompted Braun to master calculus and trigonometry so he could comprehend the physics of rocketry.
  • From his teenage years, Braun had held a keen interest in space flight.
    • became involved in the German rocket society, VfR.
      Wernher von Braun
      Wernher von Braun
  • As a means of furthering his hunger to build capable rockets, in 1932, he went to work for the German army to develop ballistic missiles.
  • Braun is well known for developing the V–2 ballistic missile for the Nazis during World War II.
  • The V–2s were constructed at a forced labor factory called Mittelwerk.
  • Scholars are still reassessing his role in these controversial activities
  • In 1960, after spending some time with the U.S. Army, he transferred to
    the newly established NASA
    • received a commission to build the giant Saturn rockets.
  • Accordingly, Braun became director of NASA’s Marshall Space Flight Center
    • Also became chief architect of the Saturn V launch vehicle, the superbooster, that would propel Americans to the Moon.[3]
  • The development of these rockets allowed humanity to reach further than ever before
    • propelled the funding and public enthusiasm for space travel, exploration, and research.


Wernher von Braun Interviewed by Tom Lehrer

external image 200px-Hebrew_timeline.svg.pngNational Geographic Space Exploration Timeline



Jonas Salk – Polio Vaccine

Shopkeeper shows his appreciation for Dr. Salk and his vaccine
Shopkeeper shows his appreciation for Dr. Salk and his vaccine


  • In 1947, Salk enrolled in the University of Pittsburgh Medical School.
  • While working there, Salk saw a chance to develop a vaccine against polio.
    • devoted himself to this work for the next eight years
  • In 1955, human trials of the polio vaccine effectively defended the subject from the polio virus.
  • When news of the breakthrough was made public in 1955, Salk was acclaimed as a miracle worker.
  • He further endeared himself to the public by refusing to patent the vaccine.
    • Salk had no desire to profit personally from his breakthrough
      • he merely wished to see the vaccine dispersed as widely as possible.
  • Salk's vaccine was comprised of the killed polio virus.
  • A few years later, the Sabin vaccine gained widespread use because it could be executed orally.
    • Salk's original vaccine required injection.
    • Made from the live polio virus
      • The few new instances of polio written of in the United States in recent years were actually caused by the live vaccine which was meant to prevent the outbreak of polio.
  • Salk's vaccine has recently begun to replace the Sabin vaccine where wild polio virus has been eliminated.
  • Jonas Salk's last couple of years were spent researching for a vaccine against AIDS.
  • He died in 1995 at the tender age of 80.[4]
  • Due to the research of Salk and the widespread distribution of the vaccine around the globe, polio has now been nearly eradicated.
  • The vaccinations against deadly diseases such as polio along with smallpox, and rinderpest
    • which have both been completely eradicated
    • some of the great achievements of science
  • These vaccines have saved and continue to save countless lives.

History of Vaccines: Website dedicated to exploration of the history of vaccines.

Click here for what life was like before the polio vaccine.

external image Essener_Feder_01.pngThis site has a biography of Salk, a long interview complete with video clips, and a photo gallery.


James Watson, Francis Crick - DNA and the Human Genome Project

  • Researchers and thinkers such as Charles Darwin, Gregor Mendel, and Thomas Hunt Morgan had speculated and tested out the mechanisms of heredity.
Watson and Crick's double helix model for the structure of DNA
Watson and Crick's double helix model for the structure of DNA


    • the chemical basis of heredity was still unknown until the pioneering work of James Watson and Francis Crick
    • discovered the double helix structure of DNA in 1953
  • This work determined the molecular structure of DNA, and how it was essential to the passing on of hereditary information through living generations.
  • This began the "Neo-Darwinian Synthesis" in modern biology which has led to our present understanding of evolution, genetics, and heredity.

external image Double_Helix.png

  • Studies of DNA had revealed much about its chemical and physical nature
    • Watson believed that its function could not be understood fully until its structure was known.
  • Crick and Watson used the results from previous studies and X-ray diffraction data from Maurice Wilkins and Rosalind Franklin to help them determine DNA's molecular structure.
  • By 1953 they had:
    • built a model which incorporated all known features of DNA
    • proposed the double helix structure which is commonly referred to as the Watson-Crick model of DNA.
  • Crick, Watson and Wilkins were awarded a Nobel prize for this work in 1962.[5]

Completed in 2003, the Human Genome Project (HGP) was a 13-year project coordinated by the U.S. Department of Energy and the National Institutes of Health
Project goals were to:

  • identify all the approximately 20,000-25,000 genes in human DNA,
  • determine the sequences of the 3 billion chemical base pairs that make up human DNA,
  • store this information in databases,
  • improve tools for data analysis,
  • transfer related technologies to the private sector, and
  • address the ethical, legal, and social issues (ELSI) that may arise from the project.

Though the Human Genome Project is finished, the data will be analyzed for many years to come. The completion of the Human Genome Project has led to the possibility of genetic testing, which can tell people about their innate predispositions and potential susceptibility to diseases and pitfalls. See below for more information on genetic tests available today. In addition to humans, scientists have also now completed the genome for hundreds of different organisms, from monkeys to whales to fungi to bacteria; see below for a complete list.

external image Essener_Feder_01.png1953: A Structure for Deoxyribose Nucleic Acid: Annotated version of the original 1953 paper authored by Watson and Crick.


Maclyn McCarty (geneticist), Francis Crick, and James Watson
Maclyn McCarty (geneticist), Francis Crick, James Watson

external image Essener_Feder_01.pngHuman Genome Project 2003 Press Conference: Original 2003 press conference announcing the completion of the Human Genome Project.

What is Genetic Testing?: Basic information about the types of genetic testing available today.

List of Completed Genomes

Human Genome Project Archives: This site has a huge number of resources for exploring the Human Genome Project.


DNA Interactive provides a number of fun interactive activities for learning about DNA and genetics, including an interactive timeline.


Women Scientists


  • Contributions of women physicists and astronomers: http://cwp.library.ucla.edu/ (Includes historical documents and primary sources, photo galleries, etc)


  • The PBS series on Women in Science also includes info about the forgotten women scientists who contributed greatly to the double helix breakthrough, yet were ostracized and undervalued. "Rosalind Franklin, the physical chemist whose x-ray photographs helped prove that the structure of DNA really was a double-helix, was often inaccurately described as an assistant to Maurice Wilkins. To add insult to injury, Watson and Crick's final breakthrough owed a great deal to the fact that Wilkins passed on Franklin's lab results without her knowledge or consent."Students could read this article and discuss lingering impacts of sexism in science and research.

Hedy Lamarr, Actresses and Inventor

Rosalind Franklin, Molecular Biologist

Barbara McClintock, Botanist and Geneticist

Scientists of Color & Scientists from the Developing World in the 20th Century


  • There were many scientists of color whose work has yet to be recognized. This National Geographic link has pictures and info of famous Black Inventors and Pioneers of Science including George Washington Carver (alternative farming methods), Madame CJ Walker (hair chemicals), and Percy Julian ("soybean chemist").
    • Lesson plan idea would be to have a discussion about colonization, slavery, and racism to get students to critically think about what factors were hindering scientists of color and scientists in the developing world to be recognized for their contributions.


LGBTQ Scientists

Alan Turing was a mathematician, computer scientist, and gay man who made important contributions as code breaker in World War II and to the development of computers.

For more, link to


Works Cited:
[1] (2006). Special Relativity. Retrieved March 14, 2007, from Stanford Linear Accelerator Center Web site: http://www2.slac.stanford.edu/vvc/theory/relativity.html
[2] (2003). Nuclear Engineering. Retrieved March 14, 2007, from The History of Nuclear Energy Web site: http://nova.nuc.umr.edu/nuclear_facts/history/history.html
[3] (2006). Wernher von Braun. Retrieved March 14, 2007, from NASA Web site: http://history.nasa.gov/sputnik/braun.html
[4] Sheed, W (1999). Jonas Salk. Time Magazine, Retrieved 3-13-2007, from http://www.time.com/time/time100/scientist/profile/salk.html
[5] Wright, R (1999). James Watson and Francis Crick. Time Magazine, Retrieved 3-13-2007, from http://www.time.com/time/time100/scientist/profile/watsoncrick.html
[6] (2006). Human Genome Project Information. Retrieved March 14, 2007, from genomics.energy.gov Web site: http://www.ornl.gov/sci/techresources/Human_Genome/home.shtml

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