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Chinese used fingerprints to establish the identity of documents and clay sculpture, but without any formal classification system.

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The event I want to remember is a significant milestone in the history of forensic science. It showcased the groundbreaking discovery that fingerprints are unique to each individual, leading to the recognition of fingerprints as a reliable method for identifying people. This discovery revolutionized law enforcement and investigative procedures. Fingerprint analysis has since become an indispensable tool in solving crimes and establishing the identity of individuals. In contemporary times, fingerprints play a crucial role in confirming or refuting a person's identity and connecting different crime scenes .

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A Chinese book, Hsi Duan Yu (the washing away of wrongs), contains a description of how to distinguish drowning from strangulation. This was the first recorded application of medical knowledge to the solution of crime

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The event in question holds significant historical importance because it marked the earliest documented instance of applying medical expertise to solve criminal cases. This innovative approach paved the way for the intersection of medicine and criminology, leading to advancements in forensic science and the development of investigative techniques that are still used today.

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Marcello Malpighi, a professor of anatomy at the University of Bologna, noted fingerprint characteristics. However, he made no mention of their value as a tool for individual identification.

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The significance of this event lies in its status as the first documented scientific observation of fingerprint characteristics. It is noteworthy that although Malpighi himself did not initially realize the potential for using fingerprints as a means of individual identification, his pioneering work in this area established the fundamental principles that would underpin future advances in the field of forensic science.

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<img src="https://worldkings.org/Userfiles/Upload/images/14767907935_72502905ba_b.jpg" alt="WCSA - On This Day - July 28, 2022 - Fingerprints were used as a means of  identification for the first time, in 1858 - WCSA.WORLD">

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In Lancaster, England, John Toms was convicted of murder on the basis of the torn edge of wad of newspaper in a
pistol matching a remaining piece in his pocket. This was one of the first documented uses of physical matching.

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This was the first time that physical comparison was used to solve a crime, which is important because today this kind of evidence is often seen and used. The community viewing this is important because they can see how much we have advanced in physical forensic science and how it all started.

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Thomas Bewick, an English naturalist, used engravings of his own fingerprints to identify books he published.

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Thomas Bewick, and English naturalist, used engravings of his own fingerprints to identify books he published

This event is notable because it shows an early practical application of fingerprints for personal identification, predating formal forensic use.

It underscores the innovative ways people have used unique biological markers for authentication purposes.

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William Nichol invented the polarizing light microscope

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The invention of the microscope has revolutionized the field of forensic science by providing the ability to closely examine and photograph specimens at a microscopic level. This powerful tool is utilized globally and plays a crucial role in forensic investigations, allowing forensic scientists to analyze evidence with precision and accuracy. Microscopes have become an indispensable asset in the forensic science world, aiding in the examination of trace evidence, biological samples, and other crucial components of criminal investigations

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The invention of the microscope has revolutionized the field of forensic science by providing the ability to closely examine and photograph specimens at a microscopic level. This powerful tool is utilized globally and plays a crucial role in forensic investigations, allowing forensic scientists to analyze evidence with precision and accuracy. Microscopes have become an indispensable asset in the forensic science world, aiding in the examination of trace evidence, biological samples, and other crucial components of criminal investigations

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Jean Servals Stas, a chemistry professor from Brussels, Belgium, was the first to identify plant poisons in body tissue.

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Jean Servals Stas was the first to be able to separate plant poison from human tissue which was helpful in the solving of a murder and marked a major advancement

in forensic toxicology evidence

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Professor R.A. Reiss, set up one of the first academic curricula in forensic science. His forensic photography department grew into Lausanne Institute of Police Science.

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This event is significant because it marks the establishment of formal education in forensic science. Reiss's efforts contributed to the professionalization and standardization of forensic practices, which are essential for reliable criminal investigations today

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Albert S. Osborne, an American and arguably the most influential document examiner, published Questioned
Documents.

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This is an important event because he was an American lawyer and pioneer in the field of forensic document examination. He is considered one of the fathers of modern forensic science and is credited with developing the fundamental principles of handwriting analysis, which are still used

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The 1920s marked the crucial period for the development of quantum mechanics

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The development of quantum mechanics in the 1920s is considered incredibly important because it revolutionized our understanding of matter at the atomic level, providing a framework to explain phenomena that classical physics could not, including the structure of atoms, the behavior of electrons, and the nature of light, laying the foundation for modern technologies like lasers, transistors, and advanced materials science

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Quantum mechanics is the branch of physics relating to the very small.

It results in what may appear to be some very strange conclusions about the physical world. At the scale of atoms and electrons, many of the equations of classical mechanics, which describe how things move at everyday sizes and speeds, cease to be useful. In classical mechanics, objects exist in a specific place at a specific time. However, in quantum mechanics, objects instead exist in a haze of probability; they have a certain chance of being at point A, another chance of being at point B and so on.

Three revolutionary principles

Quantum mechanics (QM) developed over many decades, beginning as a set of controversial mathematical explanations of experiments that the math of classical mechanics could not explain. It began at the turn of the 20th century, around the same time that Albert Einstein published his theory of relativity, a separate mathematical revolution in physics that describes the motion of things at high speeds. Unlike relativity, however, the origins of QM cannot be attributed to any one scientist. Rather, multiple scientists contributed to a foundation of three revolutionary principles that gradually gained acceptance and experimental verification between 1900 and 1930. They are:

Quantized properties: Certain properties, such as position, speed and color, can sometimes only occur in specific, set amounts, much like a dial that "clicks" from number to number. This challenged a fundamental assumption of classical mechanics, which said that such properties should exist on a smooth, continuous spectrum. To describe the idea that some properties "clicked" like a dial with specific settings, scientists coined the word "quantized."

Particles of light: Light can sometimes behave as a particle. This was initially met with harsh criticism, as it ran contrary to 200 years of experiments showing that light behaved as a wave; much like ripples on the surface of a calm lake. Light behaves similarly in that it bounces off walls and bends around corners, and that the crests and troughs of the wave can add up or cancel out. Added wave crests result in brighter light, while waves that cancel out produce darkness. A light source can be thought of as a ball on a stick being rhythmically dipped in the center of a lake. The color emitted corresponds to the distance between the crests, which is determined by the speed of the ball's rhythm.

Waves of matter: Matter can also behave as a wave. This ran counter to the roughly 30 years of experiments showing that matter (such as electrons) exists as particles.

Quantized properties?

In 1900, German physicist Max Planck sought to explain the distribution of colors emitted over the spectrum in the glow of red-hot and white-hot objects, such as light-bulb filaments. When making physical sense of the equation he had derived to describe this distribution, Planck realized it implied that combinations of only certain colors (albeit a great number of them) were emitted, specifically those that were whole-number multiples of some base value. Somehow, colors were quantized! This was unexpected because light was understood to act as a wave, meaning that values of color should be a continuous spectrum. What could be forbidding atoms from producing the colors between these whole-number multiples? This seemed so strange that Planck regarded quantization as nothing more than a mathematical trick. According to Helge Kragh in his 2000 article in Physics World magazine, " Max Planck, the Reluctant Revolutionary," "If a revolution occurred in physics in December 1900, nobody seemed to notice it. Planck was no exception ..."

Planck's equation also contained a number that would later become very important to future development of QM; today, it's known as "Planck's Constant."

Quantization helped to explain other mysteries of physics. In 1907, Einstein used Planck's hypothesis of quantization to explain why the temperature of a solid changed by different amounts if you put the same amount of heat into the material but changed the starting temperature.

Since the early 1800s, the science of spectroscopy had shown that different elements emit and absorb specific colors of light called "spectral lines." Though spectroscopy was a reliable method for determining the elements contained in objects such as distant stars, scientists were puzzled about why each element gave off those specific lines in the first place. In 1888, Johannes Rydberg derived an equation that described the spectral lines emitted by hydrogen, though nobody could explain why the equation worked. This changed in 1913 when Niels Bohr applied Planck's hypothesis of quantization to Ernest Rutherford's 1911 "planetary" model of the atom, which postulated that electrons orbited the nucleus the same way that planets orbit the sun. According to Physics 2000 (a site from the University of Colorado), Bohr proposed that electrons were restricted to "special" orbits around an atom's nucleus. They could "jump" between special orbits, and the energy produced by the jump caused specific colors of light, observed as spectral lines. Though quantized properties were invented as but a mere mathematical trick, they explained so much that they became the founding principle of QM.

Particles of light?

In 1905, Einstein published a paper, " Concerning an Heuristic Point of View Toward the Emission and Transformation of Light," in which he envisioned light traveling not as a wave, but as some manner of "energy quanta." This packet of energy, Einstein suggested, could "be absorbed or generated only as a whole," specifically when an atom "jumps" between quantized vibration rates. This would also apply, as would be shown a few years later, when an electron "jumps" between quantized orbits. Under this model, Einstein's "energy quanta" contained the energy difference of the jump; when divided by Planck's constant, that energy difference determined the color of light carried by those quanta.

With this new way to envision light, Einstein offered insights into the behavior of nine different phenomena, including the specific colors that Planck described being emitted from a light-bulb filament. It also explained how certain colors of light could eject electrons off metal surfaces, a phenomenon known as the "photoelectric effect." However, Einstein wasn't wholly justified in taking this leap, said Stephen Klassen, an associate professor of physics at the University of Winnipeg. In a 2008 paper, "The Photoelectric Effect: Rehabilitating the Story for the Physics Classroom," Klassen states that Einstein's energy quanta aren't necessary for explaining all of those nine phenomena. Certain mathematical treatments of light as a wave are still capable of describing both the specific colors that Planck described being emitted from a light-bulb filament and the photoelectric effect. Indeed, in Einstein's controversial winning of the 1921 Nobel Prize, the Nobel committee only acknowledged "his discovery of the law of the photoelectric effect," which specifically did not rely on the notion of energy quanta.

Roughly two decades after Einstein's paper, the term " photon" was popularized for describing energy quanta, thanks to the 1923 work of Arthur Compton, who showed that light scattered by an electron beam changed in color. This showed that particles of light (photons) were indeed colliding with particles of matter (electrons), thus confirming Einstein's hypothesis. By now, it was clear that light could behave both as a wave and a particle, placing light's "wave-particle duality" into the foundation of QM.

Waves of matter?

Since the discovery of the electron in 1896, evidence that all matter existed in the form of particles was slowly building. Still, the demonstration of light's wave-particle duality made scientists question whether matter was limited to acting only as particles. Perhaps wave-particle duality could ring true for matter as well? The first scientist to make substantial headway with this reasoning was a French physicist named Louis de Broglie. In 1924, de Broglie used the equations of Einstein's theory of special relativity to show that particles can exhibit wave-like characteristics, and that waves can exhibit particle-like characteristics. Then in 1925, two scientists, working independently and using separate lines of mathematical thinking, applied de Broglie's reasoning to explain how electrons whizzed around in atoms (a phenomenon that was unexplainable using the equations of classical mechanics). In Germany, physicist Werner Heisenberg (teaming with Max Born and Pascual Jordan) accomplished this by developing "matrix mechanics." Austrian physicist Erwin Schrödinger developed a similar theory called "wave mechanics." Schrödinger showed in 1926 that these two approaches were equivalent (though Swiss physicist Wolfgang Pauli sent an unpublished result to Jordan showing that matrix mechanics was more complete).

The Heisenberg-Schrödinger model of the atom, in which each electron acts as a wave (sometimes referred to as a "cloud") around the nucleus of an atom replaced the Rutherford-Bohr model. One stipulation of the new model was that the ends of the wave that forms an electron must meet. In " Quantum Mechanics in Chemistry, 3rd Ed." (W.A. Benjamin, 1981), Melvin Hanna writes, "The imposition of the boundary conditions has restricted the energy to discrete values." A consequence of this stipulation is that only whole numbers of crests and troughs are allowed, which explains why some properties are quantized. In the Heisenberg-Schrödinger model of the atom, electrons obey a "wave function" and occupy "orbitals" rather than orbits. Unlike the circular orbits of the Rutherford-Bohr model, atomic orbitals have a variety of shapes ranging from spheres to dumbbells to daisies.

In 1927, Walter Heitler and Fritz London further developed wave mechanics to show how atomic orbitals could combine to form molecular orbitals, effectively showing why atoms bond to one another to form molecules. This was yet another problem that had been unsolvable using the math of classical mechanics. These insights gave rise to the field of "quantum chemistry."

The uncertainty principle

Also in 1927, Heisenberg made another major contribution to quantum physics. He reasoned that since matter acts as waves, some properties, such as an electron's position and speed, are "complementary," meaning there's a limit (related to Planck's constant) to how well the precision of each property can be known. Under what would come to be called "Heisenberg's uncertainty principle," it was reasoned that the more precisely an electron's position is known, the less precisely its speed can be known, and vice versa. This uncertainty principle applies to everyday-size objects as well, but is not noticeable because the lack of precision is extraordinarily tiny. According to Dave Slaven of Morningside College (Sioux City, IA), if a baseball's speed is known to within a precision of 0.1 mph, the maximum precision to which it is possible to know the ball's position is 0.000000000000000000000000000008 millimeters.

Onward

The principles of quantization, wave-particle duality and the uncertainty principle ushered in a new era for QM. In 1927, Paul Dirac applied a quantum understanding of electric and magnetic fields to give rise to the study of "quantum field theory" (QFT), which treated particles (such as photons and electrons) as excited states of an underlying physical field. Work in QFT continued for a decade until scientists hit a roadblock: Many equations in QFT stopped making physical sense because they produced results of infinity. After a decade of stagnation, Hans Bethe made a breakthrough in 1947 using a technique called "renormalization." Here, Bethe realized that all infinite results related to two phenomena (specifically "electron self-energy" and "vacuum polarization") such that the observed values of electron mass and electron charge could be used to make all the infinities disappear.

Since the breakthrough of renormalization, QFT has served as the foundation for developing quantum theories about the four fundamental forces of nature: 1) electromagnetism, 2) the weak nuclear force, 3) the strong nuclear force and 4) gravity. The first insight provided by QFT was a quantum description of electromagnetism through "quantum electrodynamics" (QED), which made strides in the late 1940s and early 1950s. Next was a quantum description of the weak nuclear force, which was unified with electromagnetism to build "electroweak theory" (EWT) throughout the 1960s. Finally came a quantum treatment of the strong nuclear force using "quantum chromodynamics" (QCD) in the 1960s and 1970s. The theories of QED, EWT and QCD together form the basis of the Standard Model of particle physics. Unfortunately, QFT has yet to produce a quantum theory of gravity. That quest continues today in the studies of string theory and loop quantum gravity.
Robert Coolman is a graduate researcher at the University of Wisconsin-Madison, finishing up his Ph.D. in chemical engineering. He writes about math, science and how they interact with history. Follow Robert @PrimeViridian. Follow us @LiveScience, & .
Additional resources

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Robert Coolman - Live Science Contributor

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Quantum mechanics is the branch of physics relating to the very small. It results in what may appear to be some very strange conclusions about the physical world. At the scale of atoms and electrons, many of the equations of classical mechanics, which describe how things move at everyday sizes and speeds, cease to be useful.

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 James Watson and Francis Crick famously proposed the double helix structure of DNA

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James was considered incredibly important because it revealed the fundamental mechanism for how genetic information is stored and passed on from generation to generation, laying the foundation for modern molecular biology and enabling research into fields like genetics, medicine, and biotechnology by explaining how DNA replicates itself during cell division and how the sequence of bases within it encodes instructions for protein synthesis, essentially the blueprint of life.

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 Lawrence Morley, Fred Vine, and Drummond Matthews: Paleomagnetic stripes in ocean crust as evidence of plate tectonics

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This is important because it provided strong evidence for the theory of plate tectonics, demonstrating that the seafloor spreads apart at mid-ocean ridges, effectively validating the concept of continental drift by explaining how continents can move across the Earth's surface over time through the creation of new oceanic crust at these spreading centers

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Spencer and colleagues first identified the polymorphic nature of red cell adenosine deaminase (ADA)

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The discovery by Spencer and colleagues in 1968 that red blood cell adenosine deaminase (ADA) is polymorphic is important because it laid the groundwork for understanding the genetic basis of ADA deficiency, a condition where a lack of functional ADA enzyme leads to severe combined immunodeficiency (SCID), a life-threatening condition affecting the immune system; this finding allowed researchers to identify individuals with different levels of ADA activity and ultimately paved the way for genetic testing and research into treatments for ADA-deficient SCID.

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The FBI launched the early version of its Automated Fingerprint Identification System (AFIS) by performing the first computerized fingerprint scans.

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This important because This technology helped law enforcement to quickly and accurately match fingerprints against the database, streamlining the process of identifying suspects.

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DNA Profiling: Alec Jeffreys discovers DNA fingerprinting, a powerful technique for individual identification through DNA analysis.

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this is significant because it revolutionized forensic science by providing a highly accurate method to identify individuals based on their unique DNA patterns, allowing for the solving of crimes by linking suspects to biological evidence at crime scenes, establishing paternity in legal disputes, and even identifying missing persons, fundamentally changing the landscape of criminal investigations and personal identification.

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Thomas Caskey, a professor at Baylor University in Texas, and his colleagues were the first to publish a paper recommending the use of short tandem repeats for forensic DNA analysis.Meanwhile, Promega Corporation and Perkin-Elmer Corporation, in collaboration with Roche Molecular Systems, independently created commercial kits for forensic DNA STR typing.

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This information important because this innovation transformed DNA analysis into a standard practice in the forensic community, enhancing the ability to solve cases and uphold justice

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Roche Molecular Systems (Cetus) released a set of five additional DNA markers (polymarker) to add to the HLA- DA1 forensic DNA typing system.

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The inclusion of five extra DNA markers significantly improved the precision and accuracy of DNA profiling. This technological advancement has enabled forensic investigators to achieve more detailed and dependable identification results in their investigations.

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FBI's introduction of computerized AFIS searches.

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The implementation of computerized searches of the Automated Fingerprint Identification System (AFIS) database by the FBI, in conjunction with the use of live scan and card scan devices, brought about a groundbreaking transformation in the field of fingerprint identification. This technological advancement revolutionized the process by enabling faster and more efficient submissions, which significantly enhanced the ability of law enforcement agencies to swiftly and accurately identify and apprehend suspects.

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Andre Geim and Konstantin Novoselov isolated graphene, a monolayer of carbon atoms, and studied its quantum electrical properties.

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This is important because it opened up a new field of materials science by discovering a material with exceptional electrical conductivity, high strength, and unique quantum properties, which has the potential to revolutionize various technologies like electronics, energy storage, and composite materials, due to its single layer carbon atom structure that exhibits unusual behavior at the quantum level