Robert Andrews Millikan: Unraveling the Charge of an Electron


Robert Andrews Millikan

Robert Andrews Millikan stands out as a pivotal figure in the world of physics for his precise measurement of the elementary electric charge and extensive work on the photoelectric effect. Born on March 22, 1868, in Morrison, Illinois, he displayed an exceptional affinity for science from a young age, an interest that would eventually shape the trajectory of his professional life. He pursued higher education with great fervor, earning a doctorate from Columbia University and imbuing his academic journey with an evident passion for physics.

Throughout his career, Millikan’s explorations into the intricacies of the natural world left an indelible mark on the scientific community. In 1923, his meticulous research and groundbreaking experiments culminated in being awarded the Nobel Prize in Physics. This achievement not only solidified his place among the era’s most esteemed scientists but also had a profound impact on how future generations understood the electron and quantum mechanics.

Key Takeaways

  • Robert Andrews Millikan was a renowned physicist, celebrated for measuring the elementary electric charge and investigating the photoelectric effect.
  • He was honored with the Nobel Prize in Physics in 1923 for his significant scientific contributions.
  • Millikan’s legacy extends beyond his Nobel-winning work, greatly influencing the development of modern physics.

Early Life and Education

Robert Andrews Millikan was born in the small town of Morrison, Illinois, on March 22, 1868. He was the second son of Reverend Silas Franklin Millikan and Mary Jane Andrews, whose roots traced back to New England settlers pioneering the Midwest. Morrison offered a humble backdrop for Robert’s early years, where he developed a keen interest in the natural world around him.

From his childhood days in rural Illinois, he made the journey to Maquoketa, Iowa, where he attended high school. It was here, amid Iowa’s rolling landscapes, that Robert’s passion for education deepened.

Higher Education:

  • Bachelor’s Degree: Oberlin College
    • Subject: Classics
    • Year of Graduation: 1891
  • Master’s Degree: Oberlin College
    • Field: Physics
    • Post-Graduation Teaching: 2 Years
  • Doctorate (Ph.D.): Columbia University
    • Year Obtained: 1895

Following high school, Robert pursued his bachelor’s in the Classics at Oberlin College, a place he grew to love. It wasn’t just the books and learning that captured his heart, but also experimentation and problem-solving that started to kindle his interest in physics. Post-graduation, Robert’s affinity for the subject didn’t wane. He stayed at Oberlin to teach and to earn his master’s degree.

Oberlin was more than just an academic setting; it was where his journey in physics took shape, leading him to pursue a Ph.D. at Columbia University. There, his dedication and curiosity set him on a path to discovering some of the fundamental principles of our universe.

Scientific Achievements

Robert Andrews Millikan’s scientific work not only led to him winning the Nobel Prize for Physics, but it also established foundational aspects of modern physics. His meticulous research on the electron and the photoelectric effect contributed significantly to quantum theory and the understanding of cosmic rays.

Photoelectric Effect

Millikan conducted extensive research on the photoelectric effect, validating Albert Einstein’s photoelectric equation. He confirmed that energy is only emitted by an electron under certain conditions, lending strong support to the quantum theory that Einstein proposed.

Oil-Drop Experiment

His famous oil-drop experiment precisely measured the electric charge of a single electron. This groundbreaking work provided the first direct proof of the quantization of electric charge and determined the value of the elementary electric charge with high accuracy.

Cosmic Rays and Other Research

Millikan also investigated cosmic rays, after their discovery by Victor Hess, and provided evidence of their extraterrestrial origin. He was pivotal in confirming that cosmic rays are high-energy particles, mainly protons and atomic nuclei.

Contributions to Quantum Theory

Through his experimental evidence supporting quantum theory, Millikan helped Niels Bohr’s quantum theory of the atom to gain acceptance. His validation of quantized energy levels within the atom was a turning point for modern physics.

Educational Impact

As a physicist and professor, particularly at the California Institute of Technology, Millikan left a significant mark on physics education. He authored “First Course in Physics”, one of the most widely used physics textbooks, shaping the instruction of countless students.

Professional and Academic Career

Robert A. Millikan’s illustrious career in physics spanned from his notable time as a professor to his leadership roles in scientific organizations, earning him significant honors along the way.

University of Chicago and Caltech

His professional journey took off at the University of Chicago, where Millikan served as a professor. During his tenure, he gained fame for his meticulous work alongside Albert A. Michelson, which significantly advanced experimental physics. Their collective efforts were pivotal in establishing the norm for scientific precision.

In 1921, Millikan’s voyage in academia led him west to Pasadena, California, where he became a keystone figure at the California Institute of Technology (Caltech). There, at the Norman Bridge Laboratory of Physics, he didn’t just impart knowledge but was instrumental in transforming Caltech into a world-class institution for physics.

Organizations and Honors

Millikan played a prominent role in various organizations. He was an active member of the National Research Council and the American Academy of Arts and Sciences. His commitment to science was also recognized by the American Philosophical Society, where he was a respected figure.

His exemplary contributions to physics, particularly on the elementary electric charge and the photoelectric effect, were honored with the Nobel Prize in Physics in 1923. This acknowledgment not only celebrated his work but also underscored the international importance of his discoveries. Millikan’s influence extended far beyond the lab; he became a central figure in American science policy and a guiding voice for physicists everywhere.

Legacy and Influence

Robert Andrews Millikan left a profound mark on science, particularly in physics, both through his remarkable research achievements and his enduring influence on future generations. His contributions have been recognized globally and have paved the way for remarkable advancements in various scientific domains.

Scientific Community Recognition

Millikan’s work garnered immense respect within the scientific community. He was awarded the Nobel Prize for Physics in 1923, an honor reflecting the high esteem in which his peers held his research. Additionally, his election to the American Philosophical Society signified recognition from one of the oldest learned societies in the United States. These accolades underscore the impact of his research in physics and beyond, acknowledging his role in significantly advancing scientific understanding.

Advancements Facilitated

Millikan’s meticulous measurement of the charge of the electron laid the groundwork for a variety of scientific milestones. His findings have been instrumental in fields as diverse as chemistry, medicine, and economic sciences. For instance, the precise understanding of the electron’s charge is crucial in mRNA vaccines development, a medical breakthrough that has saved countless lives. Similarly, his work indirectly supported the growth of attosecond physics, a realm of research that operates on unimaginably brief timescales to observe electron movements. Moreover, Millikan’s dialogue on Science and Religion reflected an evolution in thought, showing a delicate balance between empirical research and philosophical inquiry, influencing both scientific communities and research institutions worldwide.

Personal Views and Controversies

Robert Andrews Millikan, notable for his work in physics, had personal views and faced controversies that cast a complex shadow on his legacy. Despite his scientific achievements, some of Millikan’s beliefs reflected the prejudices of his time, particularly regarding race and gender.

Race: Millikan was not initially a part of the Human Betterment Foundation, an organization that supported eugenic policies, but he joined its board in 1937. His involvement with such a group indicates adherence to then-common but now discredited beliefs about racial hierarchies.


  • Nurture over Nature: Millikan held traditional views about women’s roles in society, which by today’s standards, are seen as oppressive. He wasn’t alone in these beliefs, but they certainly stand in stark contrast to the current understanding of gender equality.

Science and Religion: Millikan had a more harmonious view of the relationship between science and religion. He didn’t see them as conflicting forces but rather as complementary aspects of the quest for truth. He was, perhaps, ahead of his time in this belief, considering the ongoing debate that sometimes pits these two fields against each other.

Physics and Albert Einstein:

  • Millikan had great respect for Albert Einstein and his work. Their scientific endeavors, though different in nature, were both monumental in advancing the field of physics during the early 20th century. In terms of physics, Millikan and Einstein both contributed significant knowledge that has shaped science to this day.

While he is remembered for his Nobel Prize-winning work on the electron charge and the photoelectric effect, Millikan’s views and involvement in contentious movements remind us that scientists are products of their times. It points to a larger, more human story of how societal norms influence even the most scientific of minds.

Later Years and Death

In the latter part of his life, Robert Andrews Millikan remained active in the field of physics and education. Well into his later years, he continued his work at the California Institute of Technology in Pasadena, where he had been a significant figure since its early days.

Pasadena became not only the backdrop of his professional achievements but also the place where he spent his final days. It’s there that he witnessed the fruition of his labor, as Caltech grew into a prestigious institution, in part thanks to his contributions.

  • 1923: Nobel Prize in Physics awarded to Millikan.
  • 1953: Passed away in San Marino, California, close to Pasadena.

His life came to a gentle close on December 19, 1953, in the warm Californian winter. Millikan’s departure was a quiet end to a life marked by loud achievements. His death may have stilled a vibrant mind, but the legacies he left in the worlds of science and education continue to resonate loudly even beyond the quiet streets of Pasadena.

He was laid to rest away from the clamor of the scientific community he had helped nurture, leaving behind a world that was forever changed by his discovery of the electron charge and his pivotal work on the photoelectric effect. His personal touch remains in the halls of Caltech, in the work of those he inspired, and in the advancements that were built upon his foundational discoveries.

Leave a Comment