Amelina Belanger

Written by Amelina Belanger

Modified & Updated: 03 Mar 2024

Sherman Smith

Reviewed by Sherman Smith


When it comes to influential scientists of the 20th century, Robert Andrews Millikan is a name that cannot be overlooked. Born on March 22, 1868, Millikan was an American experimental physicist renowned for his groundbreaking work on the charge of the electron and the photoelectric effect. Throughout his illustrious career, he made numerous significant contributions to the field of physics, earning him accolades and recognition from the scientific community.

But Millikan’s impact extends far beyond his scientific achievements. His relentless pursuit of knowledge, his tenacity, and his ability to communicate complex ideas in a relatable manner made him an influential figure in academia and paved the way for future scientists.

In this article, we delve into the intriguing life and career of Robert Andrews Millikan, uncovering some fascinating facts that highlight his brilliance, dedication, and lasting legacy in the realm of physics.

Key Takeaways:

  • Robert Andrews Millikan’s oil drop experiment determined the charge of an electron, earning him a Nobel Prize. His work in physics continues to inspire future scientists and advance our understanding of the world.
  • Millikan’s dedication to science education, leadership, and humanitarian causes left a lasting impact on society, emphasizing the importance of scientific curiosity, societal progress, and the coexistence of science and religion.
Table of Contents

Early Life and Education

Robert Andrews Millikan was born on March 22, 1868, in Morrison, Illinois. He had a keen interest in science from a young age and pursued a Bachelor’s degree in physics from Oberlin College.

Groundbreaking Experiment

Millikan is best known for his famous oil drop experiment, which determined the fundamental charge of an electron. This experiment provided empirical evidence for the existence of the electron and its quantized nature.

Nobel Prize in Physics

In 1923, Millikan was awarded the Nobel Prize in Physics for his work on the elementary charge of electricity and the photoelectric effect. This prestigious honor solidified his position as a leading physicist of his time.

Role in the Cosmic Ray Research

Millikan played a crucial role in advancing the understanding of cosmic rays. His experiments helped in unraveling the mysteries associated with these high-energy particles and their origin.

Academic Career

Millikan served as a professor at the University of Chicago for over three decades. During his tenure, he mentored several prominent physicists and contributed significantly to the growth of the field.

Scientific Leadership

Millikan was not only a brilliant researcher but also a visionary leader in the scientific community. He played a key role in establishing the California Institute of Technology (Caltech) as a world-renowned center for scientific research and education.

Advocacy for Science Education

Millikan was a strong advocate for science education and believed in the importance of fostering scientific curiosity in young minds. He actively promoted the teaching of science in schools and colleges.

Presidential Medal of Merit

In recognition of his contributions to science, Millikan was awarded the Presidential Medal of Merit by President Harry S. Truman in 1946.

Investigation of Cosmic Dust

Millikan conducted pioneering research on cosmic dust particles. His experiments provided valuable insights into the composition and behavior of these minuscule particles in the Earth’s atmosphere.

Contributions to Molecular Physics

Millikan made significant contributions to the field of molecular physics. His studies on the behavior of molecules in gases laid the foundation for understanding various physical and chemical processes.

Environmentalism and Conservation

Millikan was an early proponent of environmentalism and emphasized the importance of preserving natural resources for future generations. He actively supported conservation efforts and promoted sustainable practices.

Religious Beliefs

Millikan was a devout Christian and firmly believed that science and religion could coexist harmoniously. He emphasized the compatibility of scientific discoveries with religious faith.

Humanitarian Efforts

Millikan was deeply committed to humanitarian causes. He advocated for social justice, equality, and the welfare of underprivileged communities.

Patents and Inventions

Apart from his scientific pursuits, Millikan also held several patents for inventions ranging from apparatus for measuring viscosity to electrical devices.

Legacy in Physics

Millikan’s contributions to the field of physics paved the way for numerous advancements in scientific research. His work continues to inspire future generations of physicists.

Lasting Impact

The influence of Robert Andrews Millikan extends beyond his scientific achievements. His dedication to education, leadership in scientific institutions, and advocacy for societal progress have left an enduring impact.


In conclusion, Robert Andrews Millikan was a remarkable scientist who made significant contributions to the field of physics. His famous oil-drop experiment provided crucial evidence for the quantization of electric charge and the determination of Planck’s constant. Millikan’s meticulous measurements and precise calculations paved the way for our understanding of the fundamental nature of electrons. Beyond his scientific achievements, Millikan was also a dedicated educator and advocate for science education. His work continues to inspire and influence generations of scientists. As we reflect on his life and accomplishments, it is clear that Robert Andrews Millikan’s legacy will forever be engraved in the annals of scientific history.


Q: What is Robert Andrews Millikan known for?

A: Robert Andrews Millikan is known for his famous oil-drop experiment, which provided evidence for the quantization of electric charge and the determination of Planck’s constant.

Q: How did Robert Andrews Millikan’s experiment work?

A: In his oil-drop experiment, Millikan used a fine mist of oil droplets suspended between two metal plates and observed their motion in an electric field. By carefully measuring the motion of the oil droplets and taking into account various factors, he was able to determine the charge of individual electrons.

Q: What were the implications of Robert Andrews Millikan’s experiment?

A: Millikan’s experiment confirmed the discreteness of electric charge, providing strong evidence for the existence of individual electrons and their quantized nature. This experiment played a crucial role in understanding the behavior of electric charge and laid the foundation for further advancements in particle physics.

Q: What other contributions did Robert Andrews Millikan make?

A: Apart from his oil-drop experiment, Millikan was also involved in research related to cosmic rays, the photoelectric effect, and the charge-to-mass ratio of electrons. He was an influential educator, promoting scientific education and advocating for the importance of science in society.

Q: What is the significance of Robert Andrews Millikan’s legacy?

A: Robert Andrews Millikan’s legacy is significant because his work provided crucial experimental evidence for the concept of electric charge quantization. His meticulous measurements and precise calculations have shaped our understanding of the fundamental properties of electrons and have had a lasting impact on the field of physics.

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