Canada and the World
Current Events with a Canadian Perspective
Last update
28 December 2010
Science Time Line Part Eight
Charles Darwin shocks the world with his theory of evolution while others explore the beginnings of computer science and gain a better understanding of electricity
Medicine and biology are scientific fields that are fairly closely linked, and links were something biologists were keen to find.
Bryan Wright
The idea that species evolved was suspected by many at the start of the 19th century. What was missing was an explanation of why it occurred. Why did catlike creatures develop over generations, some into lions, some into tigers, and some into barnyard tabbies?
Jean-
Thus, antelopes reaching for leaves to eat from higher branches would get longer necks and, eventually, evolve into giraffes. This theory is called the “inheritance of acquired characteristics.”
Later, experiments proved that acquired characteristics can’t be inherited. But,
old Jean-
Charles Darwin’s Voyage
One of these was Charles Darwin. In 1831, he set off on a five-
Islands off the coast of South America that Darwin studied
finches.
He noticed that each island was home to a similar yet distinct species of finch that often lived off different food sources. The birds, he concluded, had developed in a way that allowed them to specialize and thrive in different surroundings. The beaks of some finches were long while others were stubby, and the shape was dictated by the type of food available.
Darwin returned to England in 1836 to write about his experiences. By 1838, he had developed his theory about how and why various species of life had different characteristics.
Later, he wrote in his autobiography that in the struggle for existence everywhere,
“favourable variations would tend to be preserved, and unfavourable ones to be destroyed...The
result of this would be the formation of new species. Here, then, I had at last got
a theory ‘-
England at this time was filled with religious evangelism. Everybody knew beyond
the shadow of a doubt that the natural world was working under the direct supervision
of God. The creation of new species of plants and animals was obviously by the hand
of God -
Charles Darwin recognized that his theory of evolution through natural selection was an enormous challenge to Christian beliefs. So he shared his ideas with only a small number of close friends. He didn’t go public until 1859, when he published On the Origin of Species.
This stirred as much controversy in society at large as the work of Copernicus. By the beginning of the 20th century, however, the fact, but not the mechanism, of evolution was generally accepted.
Early Adventures in Computer Science
We’ve seen how one development triggers another – Robert Boyle working with compressed gases led to Joseph Black’s latent heat theory and James Watt’s steam engine.
It’s possible to make the case that every transportation improvement since then is only a refinement of Watt’s first clanking, hissing, and puffing steam engine. The airplane, the automobile, and even the rocket are based on the same basic idea of getting huge amounts of propulsive power by burning fuel.
Another of these trails starts in the French city of Lyons, in 1725. Silk weavers were having a rough time producing the complex patterns their customers were demanding. The weavers used young boys to pull drawstrings in a specific order so that the shuttle passed over some and under others, so creating the pattern. But, young boys get tired and make mistakes.
Joseph Marie Jacquard developed a system of cards with punched holes in them (right).
Where there were holes a needle passed through tripping a drawstring. Where there
was no hole, the needle remained in place. The punched card didn’t get tired and
cranky so it produced a pattern that didn’t vary. If you wanted a different pattern
you used a different card.
What M. Jacquard invented, although he probably didn’t realize it, was the binary system, which was to become the foundation of digital computers.
Charles Babbage used the punched card idea to control his steam-
In the U.S., Herman Hollerith used the newly available electricity to power his mechanical
calculator; still using Jacquard’s punched card binary system. In fact, punched cards
were used right through the vacuum tube (1950s) and transistor (1960s-
Harnessing the Power of Electricity
While steam power was driving the economy onwards and upwards, the science behind the next major leap forward was being developed.
Hans Christian Ørsted’s discovery (see left above) demonstrated that electric currents produce magnetic fields. Two years later, the English physicist Michael Faraday (below)set up an electrical circuit that included two wires and two magnets.
In one case, the wire was fixed and the magnet was movable. In the other, the magnet
was fixed and the wire was movable. When Faraday passed current through the wire,
the movable wire revolved around the fixed magnet.
At the same time, the movable magnet revolved around the fixed wire. Michael Faraday had demonstrated, for the first time, that electrical forces could produce motion.
What Faraday did was far more than uncover the principles upon which electric motors might be built. He saw magnetism as a field that stretched out from its point of origin and grew weaker with distance. He said you could draw imaginary lines in the field connecting all points of equal magnetic intensity and called them “lines of force.”
This was the beginning of the concept that is at the heart of physics today: that the Universe consists of fields, of which particles are the origin.
That was for the particle physicists of today to worry about, for now Faraday’s revolving magnets and wires could be put to practical use.
In 1831, Michael Faraday built the first electric generator. But, it would have been useless if the American physicist Joseph Henry hadn’t invented the electric motor in the same year. The electric motor took the electricity of the generator and turned it into work.
The harnessing of electrical energy was to spell the end for steam power, but that was a century in the future. For now, several scientists were focussing their minds on the relationship between energy and heat.
Isaac Newton had said that a moving body would move forever unless impeded by an outside force. So, we know that a ball rolled along the ground will eventually stop. That’s because the outside forces of friction and air resistance halt it. But, what happens to the energy that started the ball rolling?
James Prescott Joule started to experiment. The energy doesn’t disappear, he discovered, it’s turned into another form – heat. In Germany, Herman von Helmholtz had come to the same conclusion. Bingo! The first law of thermodynamics was born in 1847.
The total amount of energy is the Universe is constant; none can be created and none can be destroyed. Electricity, magnetism, chemical energy, kinetic energy, light, sound, and heat can be converted one from the other.
This seemed to suggest the energy was available to be used over and over again. The German physicist Rudolf Clausius blew that lovely idea out of the water in 1850 with the second law of thermodynamics.
Some energy was always lost as heat, and heat could never be converted completely to any other form of energy. As a result, the energy supply of the Universe was constantly being degraded to heat. That meant that the amount of useful energy was constantly declining. Not to worry though, it would be trillions of years before the Universe ran out of energy.
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CREATIONISM
Although Darwin’s notion that life forms evolved through natural selection is widely accepted in the scientific community not everybody believes it.
Fundamentalist Christians hold to the Biblical teaching that God created all life on Earth and have opened several Creation Science museums to challenge Darwin’s theory.
1811
The extravagantly named Lorenzo Romano Amedeo Carlo Avogadro, conte di Quaregna e di Cerreto proposes equal volumes of all gases at the same temperature and pressure contain the same number of molecules; this has become known as Avogadro’s Principle. He is the first to draw a distinction between molecules and atoms.
1820
Danish physicist Hans Christian Ørsted is giving a lecture about the possibility
that electricity and magnetism are related. In mid-
1822
Huge bones have been found since ancient times giving rise to Chinese legends of dragons and Greek and Roman stories of ogres and griffons. However, in 1822, geologist William Buckland is poking about in a cave in Yorkshire, England and uncovers some gigantic teeth. Two years later, he describes the find in a paper entitled Notice on the Megalosaurus or Great Fossil Lizard of Stonesfield. It was not until 1842 that Sir Richard Owen gave a name to the entire genus of animals the first member of which Buckland had stumbled on. Owen called them dinosaurs, coming from Ancient Greek words meaning “terrible lizards.” Although Buckland gets most of the credit for identifying dinosaurs first, others such as Mary Anning and Gideon Mantell also found dinosaur fossils in England at around the same time.
1828
The German chemist Friedrich Wöhler is toiling away in his lab trying to synthesize a chemical when he keeps producing a white powder. He analyzes the powder and discovers he has created urea, and organic compound. This turns the previously believed theory of vitalism on its head; until Wöhler’s accidental creation of urea, it was assumed that organic chemicals could not be created outside a living organism. This marks the beginning of the field of organic chemistry.
1833
The French chemist Anselme Payen identifies the first enzyme, diastase.
1838
Three German botanists, Matthias Jakob Schleiden, Theodor Schwann, and Rudolf Virchow discover that all plants are made of cells. They suspect that the nuclei of the cells are important in cell reproduction. It is 40 years before their suspicion is confirmed. While still not understanding cell division, the Austrian monk Gregor Mendel is able to explain the laws that governed heredity.
1839
Louis Jacques Daguerre is generally called the father of photography, although others had taken photographs much earlier. However, the daguerreotype produces the best image so far even if the exposure time is 20 minutes.
1844
The American artist (not a scientist), Samuel Morse, demonstrates a telegraph machine in which a series of dots and dashes representing letters of the alphabet are transmitted across a wire. The age of telecommunication opens. Skilled operators can send messages at up to 40 words per minute.
1848
Scottish mathematician Lord William Kelvin identifies absolute zero, the coldest possible temperature in the Universe. Scientists studying deep space use the Kelvin Scale to measure extremely low temperatures; it is similar to Celsius but shifted downwards so that water freezes at 273 K and boils at 373 K. The coldest natural temperature in the Universe is 3 K; it’s theorized that this cannot drop to absolute zero, which is 0 K, because of residual heat left over from the Big Bang that created the Universe. However, scientists have created a temperature only a few billionths (0.000,000,001) of a degree above absolute zero in laboratories.
1869
The Russian chemist Dmitri Mendeleev creates the Periodic Table by arranging the
then-
1869
John Wesley Hyatt is looking for a substitute for ivory from which billiard balls are made because elephant herds are being decimated. He comes up with celluloid, the first important synthetic plastic.
1873
Scottish physicist James Clerk Maxwell ties together all previous thoughts about electromagnetism by asserting that electricity, magnetism, and light are all part and parcel of the same event. Maxwell had his hand in many scientific endeavours such as space exploration, thermodynamics, communications, mathematics, nuclear science, and engineering. He even developed a system that took the first colour photograph, of a Scottish Tartan.
THE FIRST TURBINE
The early studies of thermodynamics were motivated by the desire to derive useful work from heat energy. The first reaction turbine was described by Heron of Alexandria in about 120 AD. It consisted of a pivoted copper sphere fitted with two bent nozzles, and partially filled with water. When the sphere was heated over a fire, steam would escape from the nozzles and the sphere would rotate. The device was not designed to do useful work. It was instead a curiosity, and the nature of heat and heat transfer at that time remained mere speculation.
“The first law of thermodynamics…is usually viewed as the most basic of all the laws of Nature.”
Isaac Asimov