http://www.factmonster.com/ipka/A0932440.html
Try to imagine life without
antibiotics.
We wouldn’t live nearly as long as we do without them. Here’s a look at
some discoveries that have changed the world. It’s impossible to rank
their importance, so they’re listed in the order they were discovered.
The Copernicum System
In 1543, while on his deathbed, Polish astronomer
Nicholas Copernicus
published his theory that the Sun is a motionless body at the center of
the solar system, with the planets revolving around it. Before the
Copernicum system was introduced, astronomers believed the Earth was at
the center of the universe.
Gravity
Isaac Newton,
an English mathematician and physicist, is considered the greatest
scientist of all time. Among his many discoveries, the most important is
probably his law of universal gravitation. In 1664, Newton figured out
that gravity is the force that draws objects toward each other. It
explained why things fall down and why the planets orbit around the Sun.
Electricity
If electricity makes life easier for us, you can thank
Michael Faraday.
He made two big discoveries that changed our lives. In 1821, he
discovered that when a wire carrying an electric current is placed next
to a single magnetic pole, the wire will rotate. This led to the
development of the electric motor. Ten years later, he became the first
person to produce an electric current by moving a wire through a
magnetic field. Faraday's experiment created the first generator, the
forerunner of the huge generators that produce our electricity.
Evolution
When
Charles Darwin, the
British naturalist, came up with the theory of evolution in 1859, he
changed our idea of how life on earth developed. Darwin argued that all
organisms evolve, or change, very slowly over time. These changes are
adaptations that allow a species to survive in its environment. These
adaptations happen by chance. If a species doesn't adapt, it may become
extinct. He called this process
natural selection, but it is often called the survival of the fittest.
Louis Pasteur
Before French chemist
Louis Pasteur
began experimenting with bacteria in the 1860s, people did not know
what caused disease. He not only discovered that disease came from
microorganisms, but he also realized that bacteria could be killed by
heat and disinfectant. This idea caused doctors to wash their hands and
sterilize their instruments, which has saved millions of lives.
Theory of Relativity
Albert Einstein’s
theory of special relativity, which he published in 1905, explains the
relationships between speed, time and distance. The complicated theory
states that the speed of light always remains the same—186,000
miles/second (300,000 km/second) regardless of how fast someone or
something is moving toward or away from it. This theory became the
foundation for much of modern science.
The Big Bang Theory
Nobody knows exactly how the universe came into existence, but many
scientists believe that it happened about 13.7 billion years ago with a
massive explosion, called the Big Bang. In 1927,
Georges Lemaître proposed
the Big Bang theory of the universe. The theory says that all the
matter in the universe was originally compressed into a tiny dot. In a
fraction of a second, the dot expanded, and all the matter instantly
filled what is now our universe. The event marked the beginning of time.
Scientific observations seem to confirm the theory.
Penicillin
Antibiotics are powerful drugs that kill dangerous bacteria in our bodies that make us sick. In 1928,
Alexander Fleming discovered
the first antibiotic, penicillin, which he grew in his lab using mold
and fungi. Without antibiotics, infections like strep throat could be
deadly.
DNA
On February 28, 1953,
James Watson of the United States and
Francis Crick
of England made one of the greatest scientific discoveries in history.
The two scientists found the double-helix structure of DNA. It’s made up
of two strands that twist around each other and have an almost endless
variety of chemical patterns that create instructions for the human body
to follow. Our genes are made of DNA and determine how things like what
color hair and eyes we’ll have. In 1962, they were awarded the Nobel
Prize for this work. The discovery has helped doctors understand
diseases and may someday prevent some illnesses like heart disease and
cancer.
Periodic Table
The Periodic Table is based on the 1869 Periodic Law proposed by Russian chemist
Dmitry Mendeleev.
He had noticed that, when arranged by atomic weight, the chemical
elements lined up to form groups with similar properties. He was able to
use this to predict the existence of undiscovered elements and note
errors in atomic weights. In 1913,
Henry Moseley of
England confirmed that the table could be made more accurate by
arranging the elements by atomic number, which is the number of protons
in an atom of the element.
X-Rays
Wilhelm Roentgen, a
German physicist, discovered X-rays in 1895. X-rays go right through
some substances, like flesh and wood, but are stopped by others, such as
bones and lead. This allows them to be used to see broken bones or
explosives inside suitcases, which makes them useful for doctors and
security officers. For this discovery, Roentgen was awarded the
first-ever Nobel Prize in Physics in 1901.
Quantum Theory
Danish physicist
Niels Bohr
is considered one of the most important figures in modern physics. He
won a 1922 Nobel Prize in Physics for his research on the structure of
an atom and for his work in the development of the quantum theory.
Although he help develop the atomic bomb, he frequently promoted the use
of atomic power for peaceful purposes.
Atomic Bomb
The
legacy of the atomic bomb is mixed: it successfully put an end to World
War II, but ushered in the nuclear arms race. Some of the greatest
scientists of the time gathered in the early 1940s to figure out how to
refine uranium and build an atomic bomb. Their work was called the
Manhattan Project.
In 1945, the U.S. dropped atomic bombs on the Japanese cities of
Hiroshima and Nagasaki. Tens of thousands of civilians were instantly
killed, and Japan surrendered. These remain the only two nuclear bombs
ever used in battle. Several of the scientists who worked on the
Manhattan Project later urged the government to use nuclear power for
peaceful purposes only. Nevertheless, many countries continue to
stockpile nuclear weapons. Some people say the massive devastation that
could result from nuclear weapons actually prevents countries from using
them.
HIV/AIDS
In 1983 and 1984,
Luc Montagnier of France and
Robert Gallo of the United States discovered the HIV virus and determined that it was the cause of
AIDS.
Scientists have since developed tests to determine if a person has HIV.
People who test positive are urged to take precautions to prevent the
spread of the disease. Drugs are available to keep HIV and AIDS under
control. The hope is that further research will lead to the development
of a cure.
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