What Is The Best Science Experiment Ever Done?

Posted on | October 28, 2025 | 1 Comment

Mike Magee

Allan Franklin PhD, Professor Emeritus of Physics at the University of Colorado, cued up the question above in his acclaimed 2016 book “What Makes a Good Experiment.” He first addressed that question in a 1981 article in the British Journal for the Philosophy of Science. The general bias at the time was that science experiments had but one purpose – to test theories. But Franklin argued that “experiments can actually play a lot of different roles in science—they can, for example, investigate a subject for which a theory does not exist, help to articulate an existing theory, call for a new theory, or correct incorrect or misinterpreted results.”

One historic experiment Franklin placed at the top of his greatness list was Gregor Mendel’s famous 1856 pea experiment. The series of actions and observations spread out over a seven year period at the Augustinian St. Thomas Abbey in Brno (Brünn), Margraviate of Moravia where Mendel was a Catholic priest.

He knew more than a little about soils and plants having grown up on a farm owned by his family for 130 year. But his family was under financial pressure in his youth, and his interest in becoming a monk lay, in part, on managing a “perpetual anxiety about a means of livelihood.”

He was much more than a journeyman gardener. He was an expansive thinker with a special focus on biology and mathematics. And when it came to natural science, he didn’t lean on the traditional creation theology as much as hard core measurements, facts, and concrete deductions. It was these qualities that led to his fascination with a 10,000 year old cultivated crop that thrived in the Fertile Crescent of the Middle East – the humble pea.

Mendel was interested in charting and understanding stable variants of plants in successive generations. He choose the pea because it was a well-known and catalogue available seed at the time with easily distinguishable characteristics. He decided to concentrate on seven of these traits – plant height, pod shape, pod color, seed shape, seed color, flower position, and flower color. Between 1856 and 1863 he meticulously catalogued the progress of over 28,000 plants.

The results filled volumes of personal booklets, ultimately leading to a 40-page manual that earned him the title of “father of modern genetics” many years after his death. The observations were simple and concrete. For example, in focusing on seed color (yellow or green pea), he demonstrated that crossbreeding one yellow pea parent with one green pea parent always produced yellow pea producing children in the first generation. But in the second generation their offspring were always three yellow and one green. The same type of variation reappeared with other phenotypic traits like violet vs. white flower color.

From this, Mendel deduced that some yet to be identified biologic controllers, paired as either “dominant” or “recessive,” were directing phenotypic appearance of each plants trait. Two dominants or one dominant and one recessive pairing delivered a yellow pea in generation two. But the third generation included two recessives as an option, and therefore one of the four progeny was the recssive green pea. These invisible factors were finally defined in April, 2025, and published this year in Nature, when the full genome and all the rare controlling alleles of the humble pea were finally revealed. Image Source.

Mendel understood broadly the implications of his findings, published in 1866. But his work and insights were cited only three times in the next 35 years, and seen only as a specialized text on hybridization. Mendel alone seemed to fully understand the implications of his work. He recognized that his observations of quantitative and predictive appearance of certain phenotypic markers implied an as yet hidden biologic driver.

In 1924, three decades after his death, the scientific community acknowledged that his research was proof positive of the Law of Segregation and the Law of Independent Assortment that would ultimately underpin “Mendel’s Laws if Inheritance.” But another century would pass before experts were finally able to conclusively identify the multiple genes and complex genotype that delivered Mendel’s phenotypic findings in full.

As for Mendel’s contemporary, Charles Darwin, he either was unaware or ignored Mendel’s findings. His theories of branching patterns of evolution, natural selection occurring over millennia, and selective breeding derived from observations and careful specimen collection and notation on a 5-year voyage on the HMS Beagle from 1831 to 1836. His 1859 book On the Origin of Species omitted explicit discussion of human origins and sexual selection.

The 350 page work ends with this paragraph: “There is grandeur in this view of life, with its several powers, having been originally breathed into a few forms or into one; and that, whilst this planet has gone cycling on according to the fixed law of gravity, from so simple a beginning endless forms most beautiful and most wonderful have been, and are being, evolved.”

Thus the label “Evolution” enters common vernacular. Darwin died on April 19, 1882, two years before Mendel. Although an agnostic, the British religious community had made peace with Darwin who by then was considered the greatest scientist of his era, and was buried a hero in Westminster Abbey close to the grave of Sir Issac Newton with thousands in attendance.

As for Mendel, he was buried at the Augustinian tomb at today’s Central Cemetery in Brno. According to s final words, he had few regrets. He seemed to understand that time would have to pass before his grand experiment could be understood, and its results explained in their entirety. It’s doubtful he could have predicted that might take 170 years.

Gregor Mendel (top row, 2nd from left) and his fellow Monks.

When he first reported his results, he said:

“It requires indeed some courage to undertake a labor of such far-reaching extent; this appears, however, to be the only right way by which we can finally reach the solution of a question the importance of which cannot be overestimated in connection with the history of the evolution of organic forms. The paper now presented records the results of such a detailed experiment…. Whether the plan upon which the separate experiments were conducted and carried out was the best suited to attain the desired end is left to the friendly decision of the reader.”

In 1968, Swedish geneticist, Ake Gustafsson, in an article titled, “The Life of Gregor Johann Mendel: Tragic or Not?” summed it up well: “This is the life of Gregor Johann Mendel—reasonably long, kind, charming, great. His was a good heart. His is an imperishable fame.”

Comments

One Response to “What Is The Best Science Experiment Ever Done?”

Mike Magee
October 28th, 2025 @ 6:52 pm

“By now, the stories of Charles Darwin’s finches, Gregor Mendel’s peas, and Alfred Wallace’s wide traveling naturalist studies have become common lore both in and outside the world of biological sciences. But their long reaching conclusions helped to spur the explosion of growth in the area of biology for the last 170 years. And while it would take the discovery of DNA in the 1950s to sow the seeds of genetic evolutionary studies, we all owe a debt to these naturalist founders who laid the groundwork for many of the things we now take for granted while conducting our research.” Source: https://goldbio.com/articles/article/15-Great-biological-discoveries-that-revolutionized-life-science?srsltid=AfmBOop57jHWhv07vPj7MM1D9vi5YOnWebrsxV61KjZnmRagGlMvVJI-