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#2317-Feature:
Full Spectrum
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NEWSMAKER
FROM THE PAST
 Galileo
“The
Bible tells us how to make it to Heaven, not how Heaven is made.”
1615, Cesare Cardinal Baronio
In
1633 the Roman Catholic church hauled Galileo Galilei, an astronomer,
before the Pope’s court, the Inquisition, and forced him
to deny what he had seen with his own eyes: the earth revolves
around the sun. More than 300 years later the same church
pardoned him and acknowledged the truth of his discovery.
Despite the censorship of Galileo’s ideas, they lived on
in other people’s writings and discoveries.
When
Galileo came up with observations about the stars, both ancient
philosophers and the Church had believed that the earth was the
center of the universe for several centuries. By arguing
with them, Galileo threatened the authority of a religious system
that asked its followers to accept many beliefs on blind faith.
Disagreeing with the church was called heresy, a serious crime
punishable by torture and sometimes death. To avoid punishment,
Galileo bowed before the charge of heresy and denied his observations,
but later he passed his ideas on to his son and others.
Galileo
made his first discovery at the age of 20 when he timed a lamp
swinging above his head using the beat of his pulse. He observed
that no matter how wide the lamp swung, it always took the same
amount of time. This was called the Law of the Pendulum.
Clocks kept time using pendulums until the 1950’s when electricity
replaced pendulums as regulators. You can still see the law of
the pendulum in action in a grandfather clock.
Galileo
used his observational powers and scientific reason to discover
other laws and tools over the next few decades. He found
that objects of unequal weight drop at the same speed, The Law
of Falling Objects. He invented a thermometer to measure
heat, a hydrostatic balance to measure the gravity of materials
like gold and silver, and a microscope to look at insects.
But the discoveries he found using a telescope shook the world
he lived in more than any others did.
When
Galileo heard of a spyglass made by a Dutch eyeglass maker, he
was fascinated. He built one for himself that magnified
objects thirty-three times their size and turned it to the sky,
creating the first astronomical telescope. He published
his findings in a book called The Starry Messenger and became
famous. After a few decades he published another book that
became a best seller. In it three characters debated whether
the center of the universe was the earth or the sun. One of the
characters that was portrayed as ignorant seemed to be the Pope.
Galileo had gone too far. The Pope called him before the
Inquisition.
Although
he took back what he said under pressure of possible death, Galileo
was placed under house arrest for the rest of his life. Four years
later he went blind from an infection. Fortunately his son
and two other assistants helped him continue to write –
though not about the sky. He wrote about force and motion
and his work became the basis for some of Isaac Newton’s
ideas.
Galileo’s
influence extends beyond the realm of astronomy. Sometimes he
is called the father of modern science, because he thought it
was important to test ideas through experiments, before he accepted
them as the truth.
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WHERE
IN THE WORLD
With
a dish measuring 1000 feet in diameter, 167 feet deep, and covering
an area of about twenty acres, this enormous radio telescope,
located at the Arecibo Observatory in Arecibo, Puerto Rico, is
by far the biggest telescope in the world. The surface,
made up of almost 40,000 aluminum panels, acts as a super-magnet,
collecting radio waves from the deepest parts of space.
The waves then reflect upward towards a 900 ton platform.
A huge dome attached to this platform then focuses the waves toward
several antennae that hang below. Astronomers can easily
interpret these waves, which is very beneficial, because they
can then effectively learn much more about our Solar System, our
Galaxy, and even the farthest reaches of the Universe!
Use
the latitude and longitude coordinates below to find other big
telescopes located at these observatories around the world:
 1)
32:39N, 105:42W
2) 32:50N, 109:42W
3) 19:44N, 155:05W
4) 33:19N, 116:53W
5) 29:15S, 70:44W
6) 31:16S, 149:17E
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AN
ASTRONOMER AMONG US
 Eric
Fiegelson, an Astronomer and Astro-Physicist at Penn State University,
sure knows a lot about the sky. Click below to see and hear
what he has to say.
To
contact Eric with any questions you may have about Astronomy, feel
free to send him an e-mail: edf@astro.psu.edu
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 IMAGINE
THAT!
When
scientists search deep space, they’re often looking for
objects they’ll never see. Black holes, for example, give
off no visible light, so scientists must instead search for objects
nearby that may be affected by the black hole.
Have
one student in your class hide an every day object underneath
a dark cloth. Then discuss ways you and your classmates might
figure out what is under the cloth without touching or looking
at the object.
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WORD
TO THE WISE
 LIGHTEN
UP!
Glass
has been an important building material ever since the Egyptians
first learned how to make it about 5,000 years ago. That’s
because it’s transparent.
The
word transparent comes from the Latin word trans, meaning “through”
and parere meaning “to show oneself.” A transparent
material allows light to pass through it without scattering the
rays. (Literally, “to show oneself through.”)
No material is completely transparent. Some light energy will
always be absorbed by the material that it passes through. The
thicker the material, the more energy it will absorb. That’s
why it’s easier to see through a thin frosting of ice on
your window than to see through a thick block of ice.
The
word translucent comes from the Latin word trans and lucere meaning
"to shine." A translucent material allows some light
to shine through, but scatters the rays so much that you can’t
see clearly through it. Colored glass or white gauzy fabric are
examples of translucency.
The
word opaque comes from the Latin word opacus meaning “shade”
or “darkness.” An opaque material lets no light through.
Most metals are opaque. They may reflect light, but they don’t
let light pass through them.
Look
around your classroom for examples of transparent, translucent,
and opaque materials. Hold the objects up to a light to test them.
Try a lampshade, a book, eyeglasses, a photographic slide, a plant
leaf or petal, a ruler, a piece of paper, and a glass of water.
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GO
FIGURE!
THE
COLOR OF HEAT
In
the 1700s, the British scientist William Herschel discovered that
different colors had different temperatures. You can test his
findings for yourself.
Here’s
what you’ll need:
4
clear 2-liter bottles.
1 2-liter bottle of Pepsi, Coke, or other cola beverage.
5 thermometers
5 straws
string
red, blue, and yellow food coloring
pencil and paper
a
sunny day
Here’s
what you’ll do:
1.Fill the four empty bottles with water.
2.Add food coloring to three of the four to make one bottle each
of red, yellow, and blue water. Leave the fourth bottle clear.
3.Place all four bottles, along with the bottle of cola on a sunny
windowsill for about one hour.
4.Cut string into five 15 cm. pieces.
5.Tie one end of each string securely around a thermometer. Tie
the other end to the middle of a straw.
6.Shake down each thermometer until they all read about the same
temperature.
7.When the bottles have been on the windowsill for about an hour,
lower one thermometer into each bottle. Rest the straw across
the mouth of the bottle. The string should be short enough so
that the thermometer will be suspended about halfway between the
top and bottom of the bottle.
8.After they have been submerged for about five minutes, bring
each thermometer up and record the temperature.
9.Move the bottles away from the windowsill so they’re no
longer in sunlight. Keep them away from any heat source for 5
minutes.
10.Repeat steps 7 and 8.
Based
on your observations, which color absorbs the most heat?
Which
color reflects the most heat?
If
you placed these colors on the electromagnetic spectrum, which
order would they be in from least heat energy to most?
How
could this information be used by building or clothing designers?
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 PICTURE
THIS!
Using
the full spectrum of wavelengths, telescopes and cameras have
produced beautiful images of space. Search these sites on the
web to compile a scrapbook or bulletin board of spacescapes. Be
sure to note which types of electromagnetic waves were used to
produce each picture.
NASA’s
Origins Program
http://origins.jpl.nasa.gov/
Space
Telescope Science Institute
http://www.stsci.edu/
NASA’s
Solar System Exploration Program
http://sse.jpl.nasa.gov/
Cassini-Huygens
Mission to Saturn and Titan.
http://www.jpl.nasa.gov/cassini
The
Messier Catalog of Space Images
http://www.seds.org/messier/
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TAKE
A TOUR OF THE HUMAN BODY!
Before
his execution, convicted murderer Joseph Paul Jernigan willed
his body to science for the Visible Human Project. Soon after
his death in 1993, Mr. Jernigan’s body was sliced into 1,871
layers. Each layer was scanned into a computer creating a unique
view of the human body.
Get
beneath the surface at: http://www.nlm.nih.gov.
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TWINKLE,
TWINKLE LITTLE STARS!
See
for yourself why stars twinkle.
Here’s
what you’ll need:
-
Flashlight
- nail
- empty cereal box
- electric hot plate
Here’s
what you’ll do:
1.Use the nail to poke about a dozen small holes in one side of
the cereal box.
2.Turn on the flashlight, and stand it upright in the cereal box.
3.Close the box flaps so that the only escaping light is through
the holes or “stars.”
4.Place the hot plate on one end of a safe surface such as a table,
making sure that it doesn’t touch anything flammable, and
turn it on.
5.Place the box on the table about 20 centimeters from the hotplate
with the starry side of the box facing the hotplate.
6.Position yourself at the other end of the table so that the
hotplate is between you and the box.
7.Observe the twinkling stars!
Here’s
why they twinkle:
The
warm air from the stove rises with varying temperatures, causing
the air to have different densities. When a beam of light travels
from air of one density to another, it bends or refracts slightly.
Just as the warm air from the hotplate bends the light coming
from the cereal box, the varying temperatures and densities of
Earth’s atmosphere bend the light from stars. The scattering
starlight makes the stars seem to twinkle. But only from Earth.
In space where there is no atmosphere, stars do not twinkle.
If you have a question about Swift, please contact us via the Feedback form.
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