Tuesday, July 28, 2009

15 Scientific Discoveries that Developed the Modern World

Science gives us a way to investigate and understand the natural world, a methodology that can lead to wonderful discoveries. Often, great discoveries are made piece by piece over a period of time and involve the contributions of several people, from professional researchers to the college graduate students. Yet there are some scientific discoveries that have contributed so significantly to the wonders of our modern world that they rank particularly high on the long list of great scientific discoveries.

Five of the most important modern technological developments are listed below, along with the three most significant scientific discoveries that allowed each of them to happen. Together, these 15 discoveries form the scientific basis for our way of life.

I. The Development of Infectious Disease Prevention & Treatment


Technologies to generate and transmit electrical power, to use computers to communicate and calculate, and to launch people, experiments and communications satellites into space are certainly a big part of our modern world, but impressive developments in medicine have allowed humanity to triumph over diseases caused by the smallest, most ubiquitous life forms on Earth. This has allowed us to live longer, healthier lives – the better to enjoy all the other fruits of scientific discovery and technological development!

1. Germ Theory of Disease. Suspicion that diseases were caused by unseen ’seeds’ or living organisms goes back to the mid-1500s when physicians began tracking epidemics of infectious diseases. After Anton von Leeuwenhoek established the existence of microorganisms in the 1670s, Ignaz Semmelweis and John Snow contributed much to prevention of transmission through medical hygiene. The experiments of Louis Pasteur in the mid-nineteenth century directly supported the germ theory of disease, and he is considered the father of germ theory and bacteriology.

2. Discovery and Development of Antibiotics. Louis Pasteur later went on to discover that some microbes killed other microbes, and suggested that a microbial defense against infections might be developed. German physicians Rudolf Emmerich and Oscar Low developed pyocyanase in the 1890s from Bacillus pycyoneus, but it was unreliable in application. In 1928 Scottish biologist and pharmacologist Alexander Fleming discovered the green mold Penicillium notratum killed a staph bacillus he was working with and Penicillin soon made its debut. Now we have whole classes of antibiotics, and researchers at medical laboratories and university facilities seek new ones as their target organisms develop resistance.

3. Discovery of Viruses and Development of Vaccines. Viruses are pathogens much smaller than bacteria, discovered in the 1890s when smaller-than bacterial filters failed to stop some infectious agents. Luckily, more than a century before Edward Jenner had successfully immunized people against smallpox by infecting them with the related but less virulent cowpox. Vaccines against various viruses may be ‘live’ or ‘killed’, and have been developed against a host of epidemic-producing viruses. Over the last couple of decades the development of antiviral drugs that halt reproduction of the pathogens have been developed which can make infections less severe as the body’s own immune system develops targeted antibodies and T cells.

II. The Development of Electrical Power


The development of electrical power generation and transmission is one of the hallmarks of our modern age, contributing a great deal to our way of life. None of it could have happened without the scientific investigation that led us to understanding and control of this natural force. Many discoveries, experiments and inventions were vital to the development of the electrical system we enjoy today. The three listed were seminal, and all occurred during a time of energetic scientific investigation during the early decades of the nineteenth century.

1. The Nature of Electricity. William Gilbert described the nature of electrical charge as related to the property of amber to acquire a static charge. Since amber is ‘electron’ in Greek, Gilbert called the effect ‘electric force’. He invented the first electroscope, a device for measuring the strength of this force. It was noticed very early on that this static “attractive” force was similar to magnetism, but it was hundreds of years before the physical relationship between electricity and magnetism was established as effects of the same fundamental force.

2. The Nature of Electromagnetism. Building upon work by Hans Christian Orstead establishing that electrical currents can create magnetic fields, Andre-Marie Ampere opened the field of electrodynamics in 1820 with his demonstration that electrical currents can be positive or negative, like magnetic polarities. He later developed a precise mathematical theory that linked the forces and predicted many new phenomena.

3. Induction of Current. Michael Faraday experimented with electromagnetism and the induction of currents using an ring-coil apparatus. He could induce a current by moving a magnet through a loop of wire, or by moving the wire loop over a stationary magnet. James Clerk Maxwell modeled this as “Faraday’s Law,” which became one of the four Maxwell equations that led to modern field theory.

III. The Development of Nuclear Technologies


It would be hard to find many citizens of modern industrialized societies who are not aware of or in many ways impacted by nuclear technology. Nuclear medicine is important in our medical system, nuclear engines propel some of our off-planet explorations, nuclear boilers provide significant electrical power, nuclear waste streams are still without a final resting place, and nuclear weapons are a perennial national security issue.

1. Discovery of Sub-Atomic Particles and Isotopic Decay. Henri Becquerel was the first to document X-ray emissions from uranium, the Curies documented two other types of emissions – alpha and beta – in addition to the gamma (X-rays). Ernest Rutherford (among others) investigated elemental decay and determined that alpha particles are relatively massive helium nuclei. He also worked with single protons. It was Rutherford who first theorized about the existence of the neutron – a massive but neutral nuclear particle – confirmed in 1932 by James Chadwick. High energy physicists have since identified numerous additional sub-atomic particles of decay.

2. Discovery of Radioactive Elements Produced by Neutron Bombardment. In 1934 Enrico Fermi and collaborators discovered that bombarding uranium with neutrons could produce at least four new radioactive elements, two with atomic numbers greater than 92. It was quickly discovered that many stable elements could be made radioactive by nuclear bombardment. For instance, stable cobalt-59 becomes radioactive cobalt-60, which then decays, releasing considerable energy. It was excitedly surmised by many investigating scientists that neutron bombardment might be used to produce energy on a larger scale.

3. Discovery of Nuclear Fission. Again it was Ernest Rutherford who first split the atom (in 1917) by bombarding nitrogen with alpha particles. In 1932 his students John Cockcroft and Ernest Walton who first split atoms artificially by bombarding lithium with accelerated protons. But it took Enrico FermiEnrico Fermi to split uranium with neutrons, producing a much more energetic reaction. Fermi and a team of colleagues are credited with establishing the first artificially induced chain reaction with moderated neutrons in 1939 before going into the wartime Manhattan Project.

IV. The Development of Computation and Computers


One of the most significant tools of the modern age is the electronic computer, through which you are accessing this article. Now everything can be done through a computer: banking, shopping, and even higher education. Since electricity is covered above, below are listed the scientific/mathematical discoveries most seminal in leading to the development of the technology.

1. Binary & Boolean Logic. The Indian mathematician Pingala discovered that a sequence of zeroes and ones (binary numeral system) can be used to represent any number or value. Isaac Newton’s nemesis Gottfried Leibniz further developed a binary logic in 1703, which could also be used to designate states (on or off) as well as values (true or false). In 1854, George Boole developed a formal logic system using the symbols of algebra to represent forms and syllogisms, the “Boolean Architecture” used to mathematically model computational processes.

2. The Turing Machine. Alan Turing is considered to be the “father of modern computer science.” After spending World War II at Bletchley Park’s codebreaking center, he developed an algorithmic program called “bombe” to break the German Enigma ciphers, and contributed much to computerized encryption. He developed a thought-concept known as a “Turing Machine”, a symbol manipulation device that could model the logic of any computer algorithm. By studying the properties of the modeling, insights into complexity theory and what became computer science could be formalized for analysis.

3. Information Theory. In the late 1930s Claude Shannon established a rigorous theoretical framework that could be applied to electronic circuits, allowing them to be used as relays to solve logic problems in parallel. His 1937 master’s thesis, A Symbolic Analysis of Relay and Switching Circuits forms the foundation of practical digital circuitry in use in computers today. Shannon’s 1948 paper entitled A Mathematical Theory of Communication applied probability to information coding, useful for data compression in the transmission of information, thus file transfer protocols on the internet.

V. The Development of Space Flight


The discovery of gunpowder by Chinese alchemists in the 9th century seeking the fabled Elixir of Life was a seminal development in human history. Thanks to the simple discovery of gunpowder, we now have the military tapping it for warfare applications, citizens using it as pretty fireworks, and aeronautical professionals and students harnessing its projectile capability. It was the projectile applications that eventually led to rocketry, and our modern extraterrestrial applications in space-based communications, experimentation and exploration.

1. A Method of Reaching Extreme Altitudes. In 1919 Robert H. Goddard published his groundbreaking mathematical theories of rocket-powered flight, his experiments with solid fuel rockets, and the possibilities he saw for exploring the Earth’s atmosphere and beyond. This work, along with Konstantin Tsiolkovsky’s 1903 The Exploration of Cosmic Space by Means of Reaction Devices inspired and influenced later rocketry pioneers like Wernher von Braun, Sergey Korolev and Hermann Oberth.

2. Ballistic Missiles. Inspired by Oberth’s scientific writings and H.G. Wells’ science fiction, Wernher von Braun developed ballistic missiles for the German army after his education in aeronautical engineering. In 1941 his team designed what became the V-2 rocket, the first man-made object to achieve sub-orbital spaceflight and the progenitor of all modern rockets. After defecting to the U.S. at the end of the war, von Braun went to work for the American military and went on to develop the Redstone (a descendent of the V-2), used to launch the first Mercury manned capsules. He transferred to NASA in 1960 and developed the giant Saturn rocket, the launch vehicle that allowed Americans to explore the Moon in the 1960s and ’70s.

3. Staged Combustion. Following World War II rocket science took off in what became a “Space Race” between the U.S. and the Soviet Union, both nations making ample use of German scientists. Staged combustion is a complex application of the gas-generation cycle, and was first proposed by Aleksei Mihailovich in 1949. The Soviets put it to use in rocket engines designed to carry payloads beyond Earth atmosphere (and later, into orbit and beyond). German scientist Ludwig Boelkow tested the first Western stage-combustion engine in 1963.

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