SCIENCE
The Universe
The Sun
The Sun is an immense sphere of plasma; intensely hot, electrically charged gas, mostly hydrogen and helium. With a
diameter of 1,391,000 kilometres, it dwarfs other members of our solar system. More than one million earths could fit
into it.
As it formed from the gas and grit of the solar nebulae, the sun sucked in virtually all matter for billions of miles,
ending up with more than 98.8% of the solar system’s mass.
Nuclear fusion in its core powers the sun. The enormous heat and pressure generated within the sun’s centre, fusing
hydrogen into helium and releasing electromagnetic energy, can take hundreds of thousands of years to move from
the core, where the temperature reaches 15 million degrees Celcius, to the sun’s visible surface which is 5600 degrees
Celcius.
Magnetic fields twisting in its body pull streamers of gas far into space (solar flares). The flare ejects clouds of
electrons, ions, and atoms through the corona of the sun into space. These clouds typically reach Earth a day or two
after the event.
The Sun dominates the solar system not only through its gravitational influence, which extends up to 200,000
astronomical units away, but also through its solar wind of charged particles, which reach beyond 100 astronomical
units (far past Pluto).
An astronomical unit (AU) is 149,597, 871 kilometres, or roughly the same distance between Earth and the Sun.
The Planets
The planets where shaped by the nearby sun and ended up rocky, small and dense, with at least one, Earth, orbiting
at just the right distance to hold on to watery oceans and host the chemical of life.
The planets can be divided up into two groups of four.
Closest to the sun are the four inner planets, Mercury, Venus, Earth and Mars. The inner planets are compact and
rocky with just three moons between them. They are called terrestrial planets because they are more or less earth-like.
All of them have secondary atmospheres (produced after their formation) and at least three of them planets may once
have had oceans; Venus, whose seas may have been boiled off by the greenhouse effect; Mars, whose once liquid
oceans might now be frozen under its surface and Earth, the Blue Planet, orbiting at just the right distance from the
sun to maintain liquid water on its surface.
Far from the sun, beyond the asteroid belt, orbit the four gas giants - Jupiter, Saturn, Uranus and Neptune. These four
outer planets are huge and vaporous, possessing rings and more than 160 natural satellites between them.
Mercury
Mercury is just 4878 kms in diameter, making it the smallest of the planets. Due to Mercury’s off-centre orbit of the
sun, bringing it as close as 46 million kms to the sun at its closest point and as far as 69.82 million kms from the sun at
its furthest point, the planet see great extremes in temperature, going from highs of 427 degrees celcius to lows of -173
degrees celcius. Mercury has no natural satellites.
Venus
In size, Venus is a near match to Earth, at 12,103 kms in diameter, only 653 kms smaller than earth. Its mass is only
slightly less than that of Earth and its density and surface gravity are also close to our own planet. However, Venus
is, in fact, a smoggy furnace beneath a crushing acidic atmosphere with an average surface temperature of 462 degrees
Celcius, making it the hottest planet in the solar system. It has no natural satellites. Venus is the brightest object in
the sky from Earth other than the sun and moon and is often referred to as the Morning or Evening star.
Earth
Earth is the largest of the four terrestrial planets, at 12,756 kms in diameter. Earth is not completely spherical but
slightly wider at the centre because of its rotation. Earth is denser than other rocky planets and has a higher surface
gravity. It is the only planet with liquid water on its surface. Its surface is varied and dynamic, consisting of crustal
plates slowly shifting under a stable, shallow, moist atmosphere. Protecting Earth from radiation is the
magnetosphere, a magnetic field thousands of miles long. Earth’s only moon circles the planet at a distance of 384,400
kms away.
Mars
Known as the red planet, Mars is the fourth planet from the sun and the outermost of the rocky planets, orbiting at an
average distance of 227.9 million kms from the sun. It is roughly half the size of Earth and is now a dry, barren planet
with a surface marked by large canyon systems and huge extinct volcanos, its most famous being Olympus Mons, the
largest volcano in the solar system. Vast dust storms whip around the planet and clouds and falling snow have been
seen by spacecraft sent to explore its surface. Like Earth, Mars has seasons and ice caps and evidence suggests that
liquid water flowed across the Martian surface billions of years ago. Mars has two moons, Phobos and Deimos, both
very small moons with the largest, Phobos, being only 27 kms long and 22 kms wide.
Jupiter
Within the solar system, Jupiter is second only to the Sun is size and mass. The gas giant, at 142,984 kms in diameter,
and could hold 1300 Earths. It is almost two and a half times the combined mass of the other 7 planets put together.
Jupiter takes almost 12 years to circle the Sun but rotates once every 9.9 hours, so fast that it is more egg shaped than
sphere. Composed mainly of hydrogen and helium, like the sun, it has no real surface but a deep and windy
atmosphere over a liquid hydrogen ocean. Jupiter is not just a planet, but a planet-moon system with 63 natural
satellites, one of which, Ganymede, is the largest moon in the solar system. Jupiter’s atmosphere is affected by
colossal, oval shaped storms whipped up by the planets internal heat and very fast rotation. The largest of these
storms is the Great Red Spot which is about twice the size of Earth and has been raging for more than 350 years.
Saturn
Saturn, seen as one of the most beautiful planets with its rings, made from billions of ice particles sculpted into
multiple bands by the gravity of some of Saturn’s moons. It has 61 natural satellites, the largest of which is Titan, the
only satellite in the solar system to possess a thick atmosphere and, apparently, liquid lakes (of methane and ethane)
on its surface, possible havens for life. Saturn is 1.4 billion kms from the sun and is the second largest planet in the
solar system after Jupiter. It consists almost entirely of the lightest elements, hydrogen and helium and as a result is
the least dense planet in the solar system.
Uranus
One of the two ice giants, Uranus is the third largest planet in the Solar System and lies twice as far from the sun as
Saturn (2.9 billion kms). Neptune is pale blue in colour, which comes from the methane in its atmosphere. It is
featureless with a sparse ring system and 27 moons. As a result of what is thought to have been a collision with a
planet-sized body not long after it formed, Uranus’s spin axis is tipped over by 98%, giving it the appearance of
moving along on its orbital path on its side, with its moon encircling it from top to bottom. Its spin is retrograde –
meaning it rotates in the opposite direction to that of most other planets.
Neptune
The second of the two ice giants, Neptune is the coldest planet in the Solar System. Neptune is 4.5 billion kms from
the Sun and takes 163.7 Earth years to orbit the Sun, so has only completed one circuit since its discovery in 1846.
Neptune has a core of rock and metal, surrounded by a liquid layer of water, ammonia and methane. Above this is a
hydrogen dominated atmosphere affect by huge wind speeds of up to 2000 kms per hour – the highest wind speed
found on any planet. It has 13 moons, the largest of which is Triton.
SCIENCE
Inventions
An A – Z of some inventions that changed the world
Abacus, AD190
Use of the abacus, with its beads in a rack, was first documented in China in about AD190, but the word dates to
much earlier calculating devices. ‘Abacus’ derives from the Hebrew ibeq, meaning to ‘wipe the dust’ or from the
Greek abax, meaning ‘board covered with dust’, which describes the first devices used by the Babylonians. The
Chinese version was the fastest way to do sums and in the right hands, can still outpace electronic calculators.
Archimedes Screw, c.700BC
Purportedly devised by the Greek physicist Archimedes in the 3rd century BC to expel bilge water from creaking
ships, the screw that bears his name in fact predates Archimedes by about 400 years. Recent digs have established that
earlier screws, which are capable of shifting water uphill, were used in the Hanging Gardens of Babylon in the 7th
century BC. So effective is the device, it is still used today in several sewage plants and irrigation ditches.
Aspirin, 1899
Little tablets of acetylsalicylic acid have probably cured more minor ills than any other medicine. Hippocrates was the
first to realise the healing power of the substance – his related ancient Greek treatment was a tea made from willow
bark, and was effective against fevers and gout. Much later, in turn-of-the-century Germany, chemist Felix Hoffman
perfected the remedy on his arthritic father, marketing it under the trade name Aspirin.
Barcode, 1973
Barcodes were conceived as a kind of visual Morse code by a Philadelphia student in 1952, but retailers were slow to
take up the technology, which could be unreliable. That changed in the early 1970s when the same student, Norman
Woodland, then employed by IBM, devised the Universal Product Code. Since then, black stripes have appeared on
almost everything we buy.
Battery, 1800
For the battery we must thank the frog. In the 1780s, the Italian physicist Luigi Galvani discovered that a dead frog's
leg would twitch when he touched it with two pieces of metal. Galvani had created a crude circuit and the
phenomenon was taken up by his friend, the aristocratic Professor Alessandro Volta, whose voltaic cells stacked in a
Voltaic pile amazed Napoleon. The pile was also the first battery, whose successors power more than a third of the
gadgets on this list.
Biro, 1938
Had the Hungarian journalist Laszlo José Biró kept the patent for the world's first ballpoint pen, his estate (he died in
1985) would be worth billions. As it happened, Biró sold the patent to one Baron Bich of France in 1950. Biró's
breakthrough had been to devise a ball-bearing nib capable of delivering to paper the smudge-resistant ink. Today
around 14 million Bic "Biros" are sold every day, perhaps making the pen the world's most successful gadget.
Camera, 1826
British William Talbot, inventor of one of the earliest cameras (Joseph Nicéphore Niépce had produced the earliest
surviving photograph on a pewter plate in 1826), was inspired by his inability to draw. He described one of his
sketches as "melancholy to behold", wishing for a way to fix on paper the fleeting photographic images that had been
observed for centuries using camera obscura. His early developing techniques in the late 1830s set the standard for
decades – he invented the negative/positive process – and photography began to take off, helped in large part, in
1888, by George Eastman's Kodak, the first camera to take film.
CD, 1965
For the US inventor James Russell, the crackly sound of vinyl ruined music, so he patented a disc that could be read
with a laser. Philips and Sony picked up the trail in the early 1970s, when they perfected the Compact Audio Disc or
CAD, later shortened to CD. The first discs appeared in the early 1980s and could play 74 minutes, on the insistence of
Sony chief Akio Morita, who stipulated one disc could carry Beethoven's Ninth Symphony.
Clockwork radio, 1991
With the wind-up radio, not only did deprived areas of the developing world get access to public information, but we
were gifted a true legend of invention. British Trevor Bayliss, a former professional swimmer, stuntman and pool
salesman, devised the contraption after being horrified by reports from Africa that important information wasn't
getting through to people outside the cities.
Compass, 1190
Forced to rely on natural cues such as cliffs or spits of land, as well as crude maps and the heavens, early mariners
would get hopelessly lost. Desperate for something more reliable, sailors in China and Europe independently
discovered in the 12th century lodestone a magnetic mineral that aligned with the North Pole. By 1190, Italian
navigators were using lodestone to magnetise needles floating in bowls of water. The device set humanity on the
course to chart the globe.
Digital camera, 1975
There could be no digital camera without the charge-coupled device (CCD), the "digital film" that captures images
electronically. Developed in 1969, the widget allowed the Kodak engineer Steven Sasson to build the first digital
camera, which resembled a toaster. The first, horribly blurry snap (of a female lab assistant) he took boasted just 0.01
megapixels and took almost a minute to record and display, but in those 60 seconds, Sasson had transformed
photography – today digital cameras have all but killed off film and made photographers of us all.
Dynamite, 1867
Few inventions, save perhaps the atomic bomb, can claim to have shaken the world in quite the same way as
nitroglycerine. And few inventions can have claimed so many lives. The first to succumb to the explosive force of
Dynamite was the inventor's brother; Alfred Nobel's youngest sibling perished when an early experiment to stabilise
nitroglycerine by adding a chalky material called kieselguhr, went horribly wrong. In 1896, Nobel used his Dynamite
fortune to endow the Nobel Prizes.
Fibre optic cable, 1966
In an experiment requiring nothing more complicated than two buckets, a tap and some water, the Irish scientist John
Tyndall in 1870 observed that a flow of water could channel sunlight. Fibre optics – tubes of glass or plastic capable of
transmitting signals much more efficiently than traditional metal wire – operate under the same principles and were
perfected by Charles Kao and George Hockham in 1966. Today, thousands of miles of cables link all corners of the
globe.
Flushing toilet, 1597
Sir John Harrington, author, courtier and godson to Queen Elizabeth I, is the true inventor of the flush toilet. The
miscredited Thomas Crapper, whose name helped build the urban myth that has surrounded him for centuries was
beaten to the invention by Harrington who installed lavatories for the Queen at Richmond in the late 16th century.
Fridge, 1834
The greatest kitchen convenience was the death of the greengrocer, allowing harried professionals to keep perishables
"fresh" for days at a time. But few people (greengrocers aside) would bemoan their invention. Jacob Perkins was the
first to describe how pipes filled with volatile chemicals whose molecules evaporated very easily could keep food
cool, like wind chilling your skin after a dip in the sea. But he neglected to publish his invention and its evolution was
slow – fridges would not be commonplace for another 100 years.
Internal combustion engine, 1859
It may have fallen firmly out of favour in today's green-aware world, but the importance of the internal combustion
engine is impossible to overstate. Without it, we could not drive, fly, travel by train, build factories, motor across
oceans, trim our lawns ... the list is endless. Credit for the first working internal combustion engine goes to the Belgian
inventor Étienne Lenoir, who converted a steam engine in 1859. It boasted just one horsepower and was woefully
inefficient, but spawned the billions of engines that have been built since.
iPod, 2001
Can it really be just six years since the now ubiquitous slab of sleek white plastic and polished steel burst on to the
gadget scene and helped to revolutionise the music industry? Conceived by Apple's British design luminary, Jonathan
Ive, the iPod, the largest of which can store more than 30,000 songs, has sold an astonishing 110m units in 14
incarnations (that's an average 2,000 iPods an hour).
Laser, 1960
Laser stands for Light Amplification by Stimulated Emission of Radiation. It was Albert Einstein who laid the
foundations for its development, when in 1917 he said atoms could be stimulated to emit photons in a single
direction. The phenomenon was first observed in the 1950s and the physicist Theodore Maiman built the first working
laser in 1960. His device was based around a ruby crystal that emitted light "brighter than the centre of the sun".
Lead pencil, 1564
Any schoolboy worth his salt knows pencils do not in fact contain potentially poisonous lead. And they never did; the
pencil arrived with the discovery in 1564 in Borrowdale, Cumbria, of a pure deposit of graphite, then thought to be a
type of lead. A year later, the German naturalist Conrad Gesner described a wooden writing tool that contained the
substance. Nicolas Conté perfected the pencil more than a century later by mixing graphite with clay and gluing it
between two strips of wood.
Light bulb, 1848
So new-fangled was the light bulb in the 19th century, it came with a warning: "This room is equipped with Edison
Electric Light. Do not attempt to light with match. Simply turn key on wall by the door. The use of electricity for
lighting is in no way detrimental to health, nor does it affect the soundness of sleep." Joseph Swan in fact developed a
bulb before Edison, but the pair later joined forces and share credit for creating the gadget we perhaps take for
granted more than any other.
Microchip, 1958
It is impossible to sum up how much these tiny slivers of silicon and metal have transformed our lives. They feature
in everything from toys to tanks and motorbikes to microwaves but when, in 1952, the British engineer Geoffrey
Dummer proposed using a block of silicon, whose layers would provide the components of electronic systems,
nobody took him seriously and he never built a working prototype. Six years later, US engineer Jack Kilby took the
baton and built the world's first monolithic integrated circuit, or microchip.
Microscope, 1590
When the British polymath Robert Hooke published his 1665 masterpiece, Micrographia, people were blown away by
its depictions of the miniature world. Samuel Pepys called it "the most ingenious book that I ever read in my life".
Until then, few people knew that fleas had hairy legs or that plants comprised cells (Hooke coined the term "cell").
Zacharias Janssen, a Dutch spectacle maker, had invented the first microscope in 1590, although it was then regarded
as a novelty rather than a revolution in science.
Mobile phone, 1947
There are more than two billion mobile phones in the world, and the EU is home to more "cells", as the American's call
them, than people. It is difficult to quantify the economic and social impact of the device – of all the gadgets in the
average person's arsenal, it is surely the one we would be worst off without. Those who disagree can blame Bell
Laboratories for their invention; the firm introduced the first service in Missouri in 1947. Widespread coverage in
Britain did not begin until the late1980s.
PC, 1977
The computers IBM were producing for businesses as early as the late 1950s cost about $100,000 (almost £500,000
today), so the idea of one in every home remained a dream. But that changed in the 1970s when a group of chipwielding geeks based in California began tinkering in garages. One of the brightest techies operating in what is now
dubbed Silicon Valley was Steve Jobs, whose Apple II, launched in 1977, was the first consumer PC to resemble the
machines that went on to transform our lives.
Pneumatic tyre, 1845
Back when cars relied on real horse-power and bicycles weighed a ton, travellers were forced to endure bone-jarring
rides over the bumps and potholes of the nation's primitive roads. Cue Robert Thomson, a civil engineer who realised
the potential of air to soften the way. In 1845, he patented the use of pneumatic leather tyres on bikes. In 1888, a
Scottish vet called John Dunlop devised the more durable rubber inner-tube model that helped inflate the age of the
automobile.
Printing press, 1454
For the large part of modern civilisation, the written word reigned supreme as the only means of communication. The
Chinese were the world's first printers – they practised block printing as early as 500 AD – but a German goldsmith
called Johannes Gutenberg was the first to construct a press that comprised moveable metal type, which, when laid
over ink, could print repeatedly on to paper. In 1454 he used the revolutionary system to print 300 bibles, of which 48
copies survive, each worth millions of pounds.
Radio, 1895
We were nearly denied radio by an uncharacteristic lack of foresight shown by one Heinrich Hertz who, while
demonstrating electromagnetic waves in 1888, told his students, "I don't see any useful purpose for this mysterious,
invisible electromagnetic energy." Fortunately, Alexander Popov, a Russian, and the Italian-Irish inventor Guglielmo
Marconi, saw the potential in the technology and separately sent and received the first radio waves. Marconi sent the
first transatlantic radio message (three dots for the letter "S") in 1901.
SMS, 1992
Linguist purists H8 txtspk. The Short Message Service (SMS) has developed the thumbs of a generation of
communicators who have devised their own shorthand, textspeak, to stay in touch. The British engineer Neil
Papworth sent the first (unabbreviated) text 15 years ago. It read: "MERRY CHRISTMAS". Their popularity exploded
in the late 1990s and now in the UK alone we send millions every day (a record 214 million on New Year's Eve).
Telephone, 1876
Frenchman Charles Bourseul first proposed transmitting speech electronically in 1854, but he was ahead of his time
and it took another six years before Johann Reis used a cork, knitting needle, sausage skin and a piece of platinum to
transmit sound, if not intelligible speech (that took another 16 years). Elisha Gray and Alexander Graham Bell raced to
make the first working phone in the 1870s, Bell winning in a photo-finish. Today there are 1.3 billion phone lines in
use around the world.
Television, 1925
Television has helped connect people around the world, entertained billions, and kept generations of children
occupied on lazy Sunday mornings. Not that CP Scott, editor of the Manchester Guardian, was impressed. He said in
1920: "Television? The word is half Greek and half Latin. No good will come of it." Scotsman John Logie Baird first
demonstrated TV to the public in 1925.
The internet, 1969
The simplest way to illustrate the inestimable impact of the internet is to chart the growth in the number of people
connected to it: from just four in 1969 to 50,000 in 1988; a million by 1991 and 500 million by 2001. And today - 1.2
billion, or 19 per cent of the world's population. Conceived by the US Department of Defense in the 1960s, the
internet, together with the World Wide Web, invented in 1989 by Brit techie, Tim Berners-Lee, has shrunk the world
like no other invention.
Thermometer, 1592
It is difficult to place the thermometer in the history of modern invention; it is one of those devices that would
inevitably appear – the product of no single mind. Galileo Galilei is most commonly credited, but his clumsy air
thermometer, in which a column of air trapped in water expanded when warmed, was the culmination of more than
100 years of improvement. The classic mercury-in-glass thermometer, still in use today, was conceived by Daniel
Fahrenheit in the 1720s.
Wheel, 3500BC
The wheel surely deserves a place near the top of any "greatest inventions" list; a post-industrial world without it is
inconceivable. Its invention was perhaps inevitable, but it came later than it might have done; several civilisations,
including the Incas and the Aztecs did pretty well without wheels. The earliest evidence of a wheel – a pictograph
from Sumeria (modern day Iraq) – dates from 3500BC; the device rolled West soon after that.
Zip, 1913
Credit for the device's invention goes to Gideon Sundback. In 1913, the Swedish engineer made the first modern zip to
fasten high boots. Look at your clothes and, chances are, the zip that keeps your valuables in place started life in a
factory in the Qiaotou, China. Qiaotou's zip plants manufacture an astonishing 80 per cent of the world's zips,
churning out 124,000 miles of zip each year (enough to stretch five times round the globe or half way to the moon).
SCIENCE
The Elements
A chemical element is a pure chemical substance consisting of one type of atom distinguished by its atomic number,
which is the number of protons in its nucleus. Elements are divided into metals, metalloids, and non-metals.
The periodic table is a tabular arrangement of the chemical elements. Elements are presented in order of increasing
atomic number.
Although precursors exist, Dmitri Mendeleev is generally credited with the publication, in 1869, of the first widely
recognized periodic table. He developed his table to illustrate periodic trends in the properties of the then-known
elements. Mendeleev also predicted some properties of then-unknown elements that would be expected to fill gaps in
this table. Most of his predictions were proved correct when the elements in question were subsequently discovered.
Below are some of the most common elements with their chemical symbol and atomic number.
Element
Atomic
Number
Chemical
Symbol
Hydrogen
1
H
Helium
2
He
Carbon
6
C
Nitrogen
7
N
Oxygen
8
O
Neon
10
Ne
Sodium
11
Na
Magnesium
12
Mg
Aulminium
13
Al
Silicon
14
Si
Sulphur
16
S
Chlorine
17
Cl
Potassium
19
K
Calcium
20
Ca
Chromium
24
Cr
Iron
26
Fe
Copper
29
Cu
Silver
47
Ag
Tin
50
Sn
Platinum
78
Pt
Gold
79
Au
Mercury
80
Hg
Lead
82
Pb
SCIENCE
MEDICAL ADVANCES AND DISCOVERIES
Below are some of the most important medical advances and discoveries that changed our world
Vaccination
The discovery of vaccination has helped to greatly reduce some of the world’s deadliest epidemics and diseases, from
cholera, influenza and measles, to the bubonic plague.
Edward Jenner, an English country doctor, performed the first vaccination against smallpox in 1796 after discovering
that inoculation with cowpox provides immunity. Jenner formulated his theory after noticing that patients who work
with cattle and had come into contact with cowpox never came down with smallpox when an epidemic ravaged the
countryside in 1788.
Thanks to vaccination, we no longer have to deal with some of the world’s deadliest and most infectious diseases,
which have plagued humankind for millennia.
Germ Theory
Germ theory (discovered by French chemist Louis Pasteur) allowed our scientists to find the major causes behind
disease, and created a whole new understanding of why cleanliness was important, as opposed to the old practice of
surrounding oneself with bad smells to ward off bad influences. At that time, the origin of diseases such as cholera,
anthrax and rabies was a mystery.
The discovery of germ theory helped bring the knowledge of the importance of sanitation, and is one of the biggest
factors in extending human life by prevention of disease.
Penicillin
Germ theory might have been the discovery of bacteria, but the discovery of penicillin was the moment that the
medical profession finally had a way to fight back against infections that would have once cost people their lives.
Alexander Fleming discovered penicillin, then Howard Florey and Boris Chain isolate and purify the compound,
producing the first antibiotic. Fleming's discovery comes completely by accident when he notices that mould has
killed a bacteria sample in a petri dish that is languishing in his lab's sink. Fleming isolates a sample of the mould and
identifies it as Penicillium notatum. With controlled experimentation, Florey and Chain later find the compound cures
mice with bacterial infections.
Penicillin became the starting point for a whole string of antibiotics. This new way of treatment meant that
amputations were significantly reduced, gum infections could be treated, and infections of the blood were no longer
fatal.
Anesthetics
Anesthetics are easily one of the most important medical advances in surgical operations. Between 1842 and 1846
several scientists discovered that certain chemicals can be used as anesthetics, making it possible to perform surgery
without pain. The earliest experiments with anesthetic agents — nitrous oxide (laughing gas) and sulfuric ether —
were performed mainly by dentists.
By preventing pain during surgery, surgeons were given the ability to work in completely new ways with the human
body, with a lower chance from complications such as shock, allowing them to perform more complex and intricate
surgical procedures.
X-Ray
In 1895, Wilhelm Roentgen accidentally discovered X-rays as he conducts experiments with the radiation from
cathode rays (electrons). He notices that the rays are able to penetrate opaque black paper wrapped around a cathode
ray tube, causing a nearby table to glow with florescence. His discovery revolutionizes physics and medicine, earning
him the first-ever Nobel Prize for physics in 1901.
Blood Circulatory system
William Harvey discovered that blood circulates through the body and names the heart as the organ responsible for
pumping the blood. His groundbreaking work, published in 1628, lays the groundwork for modern physiology.
Harvey was not able to identify the capillary system connecting arteries and veins; which were later described by
Marcello Malpighi.
Blood Groups
Austrian biologist Karl Landsteiner and his group discovered four blood groups and developed a system of
classification. Knowledge of the different blood types is crucial in performing safe blood transfusions, now a
commonplace medical procedure.
DNA (Deoxyribonucleic acid)
The initial discovery of DNA was made by the Swiss physician Friedrich Miescher. It was first called a “nuclein”
because it resides in the nucleus of a cell. The first correct image of DNA was produced by James D. Watson and
Francis Crick based on image diffraction by Rosalind Franklin. DNA is a person’s individual blue print and is seen as
the building block of life.
Insulin
Frederick Banting and his colleagues discovered the hormone insulin in the 1920′s, which helps balance blood sugar
levels in diabetes patients and allows them to live normal lives. Before insulin, diabetes meant a slow and certain
death.
Vitamins
Frederick Hopkins and a few other scientists discover (in the early 1900′s) that some diseases are caused by
deficiencies of certain nutrients, later called vitamins. Through feeding experiments with laboratory animals, Hopkins
concluded that these “accessory food factors” are essential to health.
The Human Retrovirus (HIV)
Competing scientists Robert Gallo and Luc Montagnier separately discovered a new retrovirus later dubbed HIV
(human immunodeficiency virus), and identify it as the causative agent of AIDS (acquired immunodeficiency
syndrome). This discovery helped in the progress towards developing drugs to help combat or slow the progress of
the disease.