Teachers Guide Scientriffic 81 - CSIRO

history oF x-rAys
Scientriffic pages 8–9
Today, it is hard to imagine a world
without x-rays. Since their discovery
in 1895 by German physicist Wilhelm
Conrad Röntgen, x-rays have become
an essential part of many scientific
fields. Röntgen stumbled across this
type of radiation whilst investigating
how electrons behaved inside
cathode tubes. When he passed an
electric discharge through a tube
covered in black paper, he noticed
a nearby screen coated in a barium
platinocyanide glow. This led Röntgen
to conclude that the tube was emitting
an unknown type of radiation.
Because it hadn’t yet been described,
he temporarily used the letter ‘x’ for
‘unknown’. The name stuck; however,
in many places – such as Germany –
they became known as Röntgen rays.
In the experiments that followed, he
found that he could record images
of solid objects onto a photographic
plate that showed various levels of
transparency. The first ever x-ray was
an image of his wife’s hand, which
revealed the bones of her hand and
the ring she was wearing. Röntgen’s
discovery excited scientists, and
experimentation with this new type
of radiation quickly began all over the
world. In 1901, he was awarded the
Nobel Prize in Physics. In Australia,
the first x-ray experiments were
carried out as early as 1896.
Queensland government ‘History
of x-ray technology’:
http://bit.ly/Q9rycq
Australian Society of X-ray
Technology:
http://bit.ly/nexlbk
NobelPrize.org:
http://bit.ly/hnrxWd
KEEP A STEP AHEAD of
YoUR STUDEnTS wITH THIS
BACKGRoUnD InfoRMATIon.
sAturn’s rings
Scientriffic pages 10–11
Saturn isn’t the only planet to have
rings: Neptune, Jupiter and Uranus
also are orbited by rings. Yet, Saturn’s
rings are the largest and the most
impressive. They were first discovered
by Galileo Galilei in 1610, who
spotted them using his telescope. He
assumed they were moons.
Scientists believe that Saturn’s rings
are made up of pieces of a torn-up
moon, and comets and asteroids
that were pulled apart by gravity
and inertia before they reached the
planet’s surface. In all, there are
millions and millions of particles
orbiting the planet. Some are the size
of dust, whilst others are as big as
houses.
To date, seven main rings have been
identified. They are named A to G
in the order they were discovered.
Interestingly, they all orbit Saturn at
different speeds.
Since 2004, the spacecraft Cassini has
been involved in an extended mission
to discover more about Saturn
rings and moons. The instruments
on board the spacecraft are still
sending valuable information and
images of Saturn back to Earth. It is
hoped that this information will tell
scientists more about the origin and
composition of Saturn’s rings.
NASA:
http://1.usa.gov/Pg3vJr
NASA:
http://1.usa.gov/Q7sbPz
http://science.howstuffworks.
com/rings-of-saturn.htm
8 St | www.csiro.au/scientriffic | Scientriffic Teacher’s Guide | September 2012
trilobites
Scientriffic pages 28–29, 40
Trilobites are one of the best
known types of fossil, due to their
distinctive shape and features and
their numbers. They are among
some of the earliest life forms to
have been preserved in such large
quantities.
According to the fossil record,
trilobites first appeared early in
the Cambrian period around 520
million years ago, at a time when
there was a huge increase in the
diversity of life forms on Earth within
a relatively short period. This time is
often referred to as the ‘Cambrian
Explosion’ by palaeontologists.
For around 270 million years,
trilobites inhabited the planet’s
seas and oceans. Around 20 000
different species of trilobites have
been classified by palaeontologists.
These species have been organised
into around 150 different families
and nine orders, which reflects the
huge diversity of trilobites. These
early arthropods became extinct
around the end of the Permian
period, along with the majority
of other organisms, in a huge
extinction event that is sometimes
nicknamed ‘the great dying’.
http://australianmuseum.net.au/
What-are-trilobites
ABC science: Giant trilobites had
complex social lives:
http://bit.ly/2ttFl
Museum Victoria:
http://bit.ly/t1p1q6
Scientriffic magazine is published six times a year (bimonthly in January, March, May, July, September and November) by CSIRo Education.
This guide is written by Catherine Healy. Correspondence concerning the Teacher’s Guide can be sent to: The Editor, Scientriffic, CSIRo
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