About the motivation: Dave Chappelle once said that “everyone is the hero of their personal story”. While that may be accurate, a more fitting characterization of my story aligns with Sarah Silverman’s observation: “We all have two modes of living: 1.) survival mode, and 2.) creative mode”.
Having survived for eighty years, retired, and endured the COVID pandemic, I found more time for creative mode, and so started this blog. These essays provide some historical background for scientific advances from the 15th to early 20th centuries for college science students.
About the author: I attained bachelor’s degrees in physics and mathematics from the University of North Carolina, Chapel Hill, in 1968. Following two years of military service, I earned a master’s degree in physics from the University of Maryland in 1972 and subsequently received a PhD in biophysics from the University of Maryland, Baltimore, in 1977. After completing postdoctoral work at the University of Maryland and Washington University, St. Louis, I taught physiology and neuroscience to first-year medical students and allied health students at the Emory University School of Medicine, Atlanta, where I conducted research in cellular neuroscience until retirement in 2011.
About the blog: There are essays on college-level history of physics and astronomy beginning in the 15th century: Due to crude instruments and incomplete understanding of physical laws, it was uncertain at this time whether the sun or Earth held the central position. Some scholars hypothesized that the sun was the center of the planetary system, which they considered the center of the universe.
One of the first to propose a heliocentric system was Nicolaus Copernicus, a well-educated Polish scholar, lawyer, mathematician, and canon of the Roman Catholic church. His complete theory was published posthumously, though some parts were released during his lifetime.
To validate Copernicus’s proposal that the Sun was at the center, it was essential to gather and analyze precise astronomical data. Danish nobleman Tycho Brahe built an advanced observatory with royal funds and meticulously recorded planetary movements. After Brahe’s premature death, his assistant Johannes Kepler used these observations and his own data to confidently place the sun at the center of the planetary system. Kepler established that planets follow elliptical paths, sweeping equal areas in equal times, and he related orbital periods to the orbit dimensions. Some of Kepler’s conclusions are presented in the essay on classical mechanics: https://ronaldabercrombie.blog/2023/12/12/iii-the-least-action-principle-of-classical-mechanics/
The Italian polymath, Galileo Galilei, a notable experimental and theoretical scientist and predecessor to Isaac Newton, clashed with the Roman Catholic Church by asserting that the sun, not the Earth, was at the center of God’s creation. As a result, and fortunately for him, he faced only house arrest and forced repentance.
Isaac Newton, one of the greatest physicists, invented calculus. A similar mathematical tool was developed by the German polymath Leibniz. Calculus was crucial for understanding velocity, acceleration, and planetary motion. Newton’s theories on motion prevailed until Einstein’s re-imagination of space and time in the twentieth century.
Things Both Seen and Unseen
Electrical Charge: Electrical power and electronic communication have become commonplace in the 21st century, enabling cell phones, radios, televisions, lighting, and digital memory. The history of electrical power began hundreds of years ago with the simple observation that rubbing together two substances (wool and amber, for example) could produce an electrical charge. Charges will attract or repel, depending on how they are generated. It was soon discovered that charge could be either positive or negative. Coulomb’s law states that the force between two charges is inversely proportional to the square of the distance separating them.
Magnetism: A steady source of electric current, a battery (then called a “Voltaic pile”), was crucial for developing an understanding of magnetism. Electromagnets, which required a steady current, were introduced by Ampere in 1820. Faraday, Ampere, Oersted, and Sturgeon showed the converse: that changing magnetic fields cause charge to move in wires.
Light: James Clerk Maxwell formulated equations based on the observations of these men, he predicted electromagnetic radiation (light) and calculated its speed using only two fixed constants, the permittivity and permeability of the vacuum: https://ronaldabercrombie.blog/2023/12/17/i-maxwells-equations/: His work helped lay the foundation for relativity theory a quarter of a century later.
Maxwell, Boltzmann, Gibbs, and Bohr made other significant contributions to chemistry, molecular motion, entropy, and modern physics, further expanding our knowledge of thermodynamics and the unseen properties of substances within our universe: https://ronaldabercrombie.blog/2023/12/14/iv-brief-summary-of-thermodynamics-and-statistical-physics/
Things unseen
The realm of modern physics: Quantum Mechanics began with J. J. Thompson’s experiments on electron beams. Electrons, often called “pseudo-particles,” exhibit wave-like characteristics as proposed by de Broglie. Bohr’s explanation of the hydrogen atom’s emission spectrum and de Broglie’s wave description of matter advanced the understanding of quantum mechanics in its early period.
Rutherford postulated that most of the atomic mass and the positive charge at the atom’s core reside in a small nucleus at its center. Schrodinger’s equation described the wave nature of electrons, while the inherent uncertainty in quantum mechanics was concisely expressed in the Heisenberg uncertainty principle: https://ronaldabercrombie.blog/2023/12/15/v-a-conversation-about-quantum-mechanics/
Relativity Theory: This concept, primarily discovered by Einstein, with contributions from Lorentz, Poincaré, and Minkowski, is founded on the seemingly straightforward postulate that the speed of light remains consistent across all frames of reference, whether steadily in motion (special relativity): https://ronaldabercrombie.blog/2023/12/17/ii-angles-and-their-role-in-special-relativity/ or accelerating (general relativity): https://ronaldabercrombie.blog/2023/12/17/vi-brief-outline-for-general-relativity/. Relativity theory significantly enhanced our comprehension of the universe.
Overview of selected topics in biology
Cellular neuroscience is a small but important subset of biology. It examines the cellular basis of intercellular connections and communication among neuronal cells: https://ronaldabercrombie.blog/2024/04/10/on-biology-and-cellular-neuroscience/
Organ physiology concerns the heart, lung, kidneys, among other organs, and their roles in homeostasis. This essay is for high school students who might be considering a career in health: https://ronaldabercrombie.blog/2024/09/02/basic-physiology-for-high-school-students/
Origin of life on earth examines the unanswered question of how life first began: https://ronaldabercrombie.blog/2024/05/14/where-physics-and-biology-intersect/ . There are relationships within the second law of thermodynamics that are discussed in this essay.
The human motivation and reaction essay is a brief look into what ancient and modern scholars have written about the human condition: https://ronaldabercrombie.blog/2025/04/22/motivations-and-reactions-in-human-behavior/
The history of seven (of the hundreds of) pharmacological agents examines the use of medicinals, which goes across many cultures and back centuries: https://ronaldabercrombie.blog/2025/06/16/pharmacology-today-and-in-ancient-natural-medicines/
An essay on How we view our location in the universe examines modern astrophysical observations. Astrophysicists agree that the universe is immense. They estimate that there are billions of galaxies akin to our Milky Way. They vary in size and many contain billions of stars. Our Sun is but one star within the Milky Way galaxy, and Earth is one of eight or nine planets orbiting our Sun. As we contemplate the vastness of the universe, the question may arise: is our location—or that of our Sun or galaxy—closer to the center of the universe or nearer its edge? Current understanding may seem surprising, for our location seems to be both at the center and at the edge of the observable universe: https://ronaldabercrombie.blog/2025/03/08/essays-for-college-physics-majors/
There are two essays that stray from the original theme: one on autocratic rule, https://ronaldabercrombie.blog/2025/12/04/science-lesson-on-autocratic-rule/, and a satire about DEI, https://ronaldabercrombie.blog/2025/12/08/satire-on-dei/
Returning finally to Sarah Silverman’s comments about creative and survival modes—There may be times when these modes intersect. This happened twice in my professional career. Once near the beginning, concerning mitochondria https://ronaldabercrombie.blog/2026/01/15/brief-history-of-mitochondrial-calcium-a-personal-reflection/ and once near the end, concerning the role of calcium buffers in calcium transport across phospholipid membranes: https://ronaldabercrombie.blog/2025/12/26/an-example-of-how-two-seemingly-contradictory-experimental-findings-may-both-be-true/
Acknowledgements: For help with this blog, I thank my wife, Jan; a remote friend, Charlie Harris, who edited some of the earlier essays; Microsoft Co-pilot, a godsend for dyslexics; and Sam Solomon, my nephew, for helping me begin this. He named the blog.
Science Essays for College Students 