What is science?
Science is the search for knowledge about the world
and the way it works. Unlike other ways of explaining
how the world works, science is based on experiments
that test theories (ideas).
BEFORE SCIENCE
In the past, people relied on ancient
stories to explain such things as how
life began, why the Sun appears to
cross the sky, what lies beyond the
oceans, and so on. These stories
often came from religious books or
from scholars who dreamed up
imaginative ideas without checking
them. Because the stories were never
tested, there were hundreds of
different versions, and every culture
had a different version of the truth.Orange juiceSCIENCE
How does science work?
Science began when people started to
check their ideas about the world.
One of the first people to do this was
an English doctor named William
Gilbert (1544–1603). He performed
many experiments on magnetism and
eventually proved that
the Earth is like a
giant magnet.Proving theories
Although scientists can prove that a
bad theory is wrong, they can never
prove that a good theory is absolutely
right. Even if a theory seems correct,
someone could always do a new
experiment in the future and prove
it wrong. So theories
always remain
theories.Testing theories
Scientists begin with an idea, or “theory.”
Imagine you have a cold but get better
after drinking orange juice. You might
form a theory that orange juice cures
colds. To test this, you could give orange
juice to people with colds. If they get
better faster than people who don’t drink
juice, the theory is
strengthened. JAPANESE MYTH says
that the gods stirred the ocean
to create the first island.TAKE A LOOK:
COPERNICUSOOne of the greatest ever scientific
theories was put forward by Polish
astronomer Nicolaus Copernicus
in 1507. His idea was that Earth
travels around the Sun, rather than
vice versa. At first, people thought
this was crazy because the Sun
moves across the sky each day, as
though it’s going around Earth.
But Copernicus discovered that
this is an illusion caused by the
Earth spinning around. COPERNICAN WORLD SYSTEM
Pictures like this showed the Sun at the
center of the universe for the first time. OLD MARINERS
COMPASS Gilbert
showed that compasses
point north because of the
Earth’s magnetism. ATOMIC
THEORY It is
still only a theory
that matter is made of atoms.ElectronProtonNeutron220c.350BCE 1543 1665 17301880
Andreas Vesalius
was a Belgian
who wrote a
seven-volume
book about
the body.Aristotle is often called the
first scientist. His ideas helped
lay the foundations of modern
sciences such as physics,
chemistry, and biology.Isaac Newton was a British
scientist. He set
out new ideas
about motion
and gravity.1687
Many scientists built
on one another’s work
to understand
electricity and turn it
into a useful source of
power.Robert Hooke was an
English scientist. He
used an early telescope
to show that cells are
the building blocks of
all living things.TIMELINE OF SCIENCE