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1681/ The earliest attempt
to organize pure substances according to chemical (and physical)
properties was the table of affinities developed in 1718 by
Etienne-Francois Geoffroy (1672-1731).
1682/ In 1kg of water
(1000 grams) there are 889 grams of oxygen and 111 grams of
hydrogen.
1683/ Between 650 and
2,900 km below the Earth's surface hot, compressed minerals
surround the planet's iron-rich core. Called the lower mantle,
this material may hold up to 0.2 per cent of its own weight
in water, estimate Motohiko Murakami, of the Tokyo Institute
of Technology in Japan.
1684/ Ballooning had
its origins in France. The Montgolfier brothers gave the first
public demonstration of a hot-air balloon on June 5th 1783.
1685/ Jean Baptiste Lamarck
(1744-1829) coined the terms 'biology' and 'invertebrate'
and developed a taxonomy system that was, in some respects,
easier to use then that of Linnaeus.
1686/ Carl Linnaeus (1707-1778),
also known as Carl von Linné or Carolus Linnaeus, is
often called the Father of Taxonomy. His system for naming,
ranking, and classifying organisms is still in wide use today
(with many changes). His ideas on classification have influenced
generations of biologists both during and after his own lifetime.
1687/ The first Chair
of Chemistry was awarded in 1769 to Dr. Benjamin Rush at the
University of Pennsylvania.
1688/ To escape the Earth's
gravitational pull you need a speed of 11 kilometres per second
(km/s) or 22,000 miles per hour (mph).
1689/ The modern chemical
dyeing industry (as opposed to dyes with origins in plant
and animal matter which have been around for millenia) can
be traced back to William Henry Perkin (1838-1907) who in
1856 found that by distilling coal tar (an unwanted waste
product at the time) he could extract an excellent purple
dye. Perkins named it 'mauve'. he then built a factory to
manufacture mauve, and the chemical dyeing industry was born.
1690/ The accidental
discovery of penicillin in 1928 by Alexander Fleming stimulated
a two-decade search for its chemical structure, ultimately
obtained in the mid-1940s by the crystallographer Dorothy
Crowfoot (later Hodgkin) (1910-1994), who received the 1964
Nobel Prize in Medicine and Physiology for her determination
of the structure of Vitamin B12.
1691/ The motto for the
Olympic Games is Citius - Altius - Fortius (Faster - Higher
- Stronger).
1692/ The air is made
up primarily of gases. It is almost entirely a mixture of
nitrogen and oxygen, but contains other gases too, and also
suspended dust and small organisms such as bacteria. The percentage
of gases (and other stuff) in the air varies with altitude,
location and humidity, and also on the particular time, as
wind, for example, plays a part in determining the air's composition.
Water vapor is the gas which varies most. In desert areas,
water vapor may account for as little as 0.1% of the air,
while in warm, humid zones, it may be as much as 6%. The higher
up we go, the less heavier particles are found in the air,
so the higher we go, the percentage of lighter gases goes
up, and there is very little dust and particles. A typical
composition of dry air is Nitrogen 78.08%, Oxygen 20.95%,
Argon 0.93%, Carbon dioxide 0.03%, neon 0.0018%, krypton 0.0011%,
helium 0.00052%, xenon 0.0000087% and minute traces of others.
1693/ Carbon dioxide
does not make up a large proportion of the air, but it is
significant. It is important because it is a greenhouse gas
and helps contribute to global warming. It is taken out of
the atmosphere by photosynthesis, and enters it by breathing,
decay, and many human activities, such as industry and car
exhausts. Carbon dioxide in the air has risen from approximately
290 parts per million by volume (ppmv) around 1900 to about
366 ppmv at the end of 1998. This is mostly due to human activities.
1694/ Every cubic metre
of air contains nearly 10 grams of argon, and each adult inhales
almost 200 grams of argon per day. Yet we were unaware of
argon's existence until 1894 when it was discovered.
1695/ In Papua New Guinea
there are villages within five miles of each other which speak
different languages.
1696/ In 1912, the German
geophysicist Alfred Wegener (1880-1930) noted similarities
in fossils collected in the two continents, combined this
with geophysical data, and postulated the theory of 'continental
drift'.
1697/ Nitrogen is obtained
at -196 degrees C. It is used primarily in chemical processing,
electronics, as a freezing agent and in fertilizers.
1698/ The existence of
an colourless, odourless substance that was given off during
combustion was first proposed during the 17th century. In
1700 Georg Ernst Stahl gave this substance the name phlogiston.
He derived it from the greek phlogistos, meaning flammable.
It was believed that substances that could be burnt did not
exist in their true form. Their true form was what was left
after combustion, and the pre-combusted form was a combination
of the substance and phlogiston. Burning the object liberated
the phlogiston, and enabled the object to assume its true
form (the calx). This process was known as dephlogistination.
1699/ A major blow to
the theory of phlogiston emerged when it was discovered that
a metal such as magnesium actually gains mass when burnt.
This lead to phlogistians proposing that Phlogiston had negative
mass! This meant that the release of phlogistion from a burning
object would cause it to gain mass, thus fitting the observations.
Eventually Lavoisier provided a much more satisfactory explanation,
that of oxidation, which is still in use today. The calx is
actually the metal oxide, and the gain in weight is due to
the addition of oxygen to the substance.
1700/ About two-thirds
of the world's population have no regular contact with newspapers,
television, radio or telephones.
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