# Materials Science and Engineering/Contributions by Scientists

## Contributions by Scientists Born in 19th Century

### Josiah Willard Gibbs (1839 - 1903)

Josiah Willard Gibbs (February 11, 1839 – April 28, 1903) was a preeminent American engineer, theoretical physicist, and chemist noted for his famed 1876 publication of On the Equilibrium of Heterogeneous Substances, a graphical analysis of multi-phase chemical systems, which laid the basis for a large part of modern-day science. As one of the greatest American scientists, he devised much of the theoretical foundation for chemical thermodynamics as well as physical chemistry. As a mathematician, he was an inventor of vector analysis.

#### Areas of Contribution

• Theoretical foundation for chemical thermodynamics
• Theoretical foundation of physical chemistry
• 1876: "On the Equilibrium of Heterogeneous Substances"

### Max Karl Ernst Ludwig Planck (1858 - 1947)

Max Karl Ernst Ludwig Planck (April 23, 1858 in Kiel, Germany – October 4, 1947 in Göttingen, Germany) was a German physicist. He is considered to be the founder of quantum theory, and therefore one of the most important physicists of the twentieth century.

#### Areas of Contribution

• Birth of quantum physics
• 1900: Electromagnetic energy only emitted in quantized form

### Albert Einstein (1879 - 1955)

Albert Einstein (March 14, 1879 – April 18, 1955) was a German-born theoretical physicist. He is best known for his theory of relativity and specifically mass-energy equivalence, ${\displaystyle E=mc^{2}}$. Einstein received the 1921 Nobel Prize in Physics "for his services to Theoretical Physics, and especially for his discovery of the law of the photoelectric effect."

Einstein's many contributions to physics include his special theory of relativity, which reconciled mechanics with electromagnetism, and his general theory of relativity, which extended the principle of relativity to non-uniform motion, creating a new theory of gravitation. His other contributions include relativistic cosmology, capillary action, critical opalescence, classical problems of statistical mechanics and their application to quantum theory, an explanation of the Brownian movement of molecules, atomic transition probabilities, the quantum theory of a monatomic gas, thermal properties of light with low radiation density (which laid the foundation for the photon theory), a theory of radiation including stimulated emission, the conception of a unified field theory, and the geometrization of physics.

#### Areas of Contribution

• Capillary Action
• Critical Opalescence
• Classical Problems of Statistical Mechanics with Application to Quantum Theory
• Law of the Photoelectric Effect
• 1905: "On a Heuristic Viewpoint Concerning the Production and Transformation of Light"
• Explanation of Brownian Movement of Molecules
• 1905
• Atomic Transition Probabilities
• Quantum Theory of a Monatomic Gas
• Thermal Properties of Light with Low Radiation Density
• Theory of Radiation Including Stimulated Emission
• 1917: Article in Physikalische Zeitschrift that proposed the possibility of stimulated emission

### Niels Henrik David Bohr (1885 - 1962)

Niels Henrik David Bohr (October 7, 1885 – November 18, 1962) was a Danish physicist who made fundamental contributions to understanding atomic structure and quantum mechanics, for which he received the Nobel Prize in Physics in 1922. He was also part of the team of physicists working on the Manhattan Project. Bohr married Margrethe Nørlund in 1912, and one of their sons, Aage Niels Bohr, grew up to be an important physicist, who like his father received the Nobel prize, in 1975.

#### Areas of Contribution

• Atomic Structure and Quantum Mechanics
• 1913: Bohr Model

### Erwin Rudolf Josef Alexander Schrödinger (1887 - 1961)

Erwin Rudolf Josef Alexander Schrödinger (August 12, 1887 – January 4, 1961) was an Austrian - Irish physicist who achieved fame for his contributions to quantum mechanics, especially the Schrödinger equation, for which he received the Nobel Prize in 1933. In 1935, after extensive correspondence with personal friend Albert Einstein, he proposed the Schrödinger's cat thought experiment.

#### Areas of Contribution

• Schrodinger equation
• 1926: "Quantisation as an Eigenvalue Problem"

## Contributions by Scientists Born in 20th Century

### Linus Pauling (1901 - 1994)

Linus Carl Pauling (February 28, 1901 – August 19, 1994) was an American scientist, peace activist, author and educator. He is considered the most influential chemist of the 20th century and ranks among the most important scientists in history. Pauling was one of the first scientists to work in the fields of quantum chemistry, molecular biology and orthomolecular medicine (optimum nutrition).

Pauling is one of a small group of people who have been awarded more than one Nobel prize, only one of two people to receive them in different fields (the other was Marie Curie) and the only person in that group to have been awarded each of his prizes without having to share it with another recipient.

In 1954 Pauling was awarded the Nobel Prize in Chemistry "for his research into the nature of the chemical bond and its application to the elucidation of the structure of complex substances". Pauling's x-ray crystallographic research in crystal and protein structure determination as a biochemist helped lead other scientists to the eventual discovery of the double helix structure of the DNA molecule, which contains the genetic instructions for the development and functioning of all living organisms on earth.

During the Second World War Pauling, an avid anti-Nazi, worked on research and development that had military applications. However, when the war ended he became particularly concerned about the further development and possible use of atomic weapons and with the destruction inflicted on the world by war in general. Ava Helen Pauling, Linus's wife of fifty-eight years, was a pacifist and in time he came to share her views.Pauling, along with others such as Albert Einstein began to express their concerns publicly. Pauling was particularly concerned with the effects of nuclear fallout and in 1962 was awarded the Nobel Peace Prize for his work in campaigning against above-ground nuclear testing. His beliefs were not without controversy at the time and he was criticized by some for his actions.

#### Areas of Contribution

• Nature of the Chemical Bond
• Structure of the Atomic Nucleus
• Biological Molecules
• Molecular Genetics

### Werner Karl Heisenberg (1901 - 1976)

Werner Karl Heisenberg (December 5, 1901 – February 1, 1976) was a celebrated German physicist and Nobel laureate, one of the founders of quantum mechanics and acknowledged to be one of the most important physicists of the twentieth century. Heisenberg was the head of the German nuclear energy project under the Nazi regime, though the nature of this project, and his work in this capacity, has been heavily debated. He is most well-known for discovering one of the central principles of modern physics, the Heisenberg uncertainty principle, and for the development of quantum mechanics, for which he was awarded the Nobel Prize in Physics in 1932.

#### Areas of Contribution

• Development of Quantum Mechanics
• 1925: Matrix Mechanics - first formalization of quantum mechanics
• Late 1920s: Copenhagen Interpretation
• Heisenberg Uncertainty Principle
• 1927: Uncertainty Principle