Embed Size (px)
Citation preview
School Department
Name
Address Postcode
Phone Fax
Email Signature Date
CUSTOMER DETAILS School order number REQUIRED FOR FIRM SALE
PROMO CODE: DRW09
CONTENTS1. Life, the universe
and everything2. The restless Earth3. Colonising other worlds4. Nuclear energy -
Australia’s energy future?
5. Weapons through the ages
6. The brave new world of genetic engineering
7. Survive that drive8. What’s your poison?9. Crime squad
Kahni BurrowsScience 21
Chapter Two The restless Earth 65
Figure 2.38:
Countries most directly affected by the 2004 Sumatra–Andaman earthquake
Science 2164
TsunamisTsunamis are ocean waves that are generated by the sudden displacement
of large volumes of water. While these displacements can be caused by
landslides or volcanic eruption, they are usually the result of movement of
the sea fl oor by earthquakes. Rather than being a single wave, a tsunami
is actually a series of waves that travel across the ocean at speeds of up to
800 kilometres per hour.
How tsunamis formWhen a large volume of water is suddenly displaced, it travels outwards
from the disturbance much as ripples move outward from the point where
a rock is dropped in a pond. In deep water, the waves can be separated by
as much as a hundred kilometres, and they can have a small amplitude
— only a metre or so — which is not noticeable to observers on ships
travelling through them or those on aircraft above them.
As the waves approach the shallower water along a coastline, the waves
slow down. Waves further back start to catch up to those in front, which
causes the waves to increase in height as they bunch up. These waves can
reach heights of 30 metres before they break onto the land. The massive
body of water moves inland, causing severe fl ooding and considerable loss
of life and property (see fi gure 2.37).
Fast-moving wavesWaves slow down in shallow water.
Crests are closer together and higher.
Seismic activity
Figure 2.37:
How tsunamis form
Case study: Boxing Day 2004The Boxing Day 2004 Tsunami (also referred to as the Sumatra–Andaman
Tsunami) was caused by an earthquake of magnitude at least 9.0, with an
epicentre located just north of Simeulue Island in Indonesia. Whereas most
earthquakes last only a few seconds, the Sumatra–Andaman earthquake
lasted several minutes and triggered secondary earthquakes in Alaska.
The tsunamis generated by the earthquake hit the coastlines of Indonesia,
Sri Lanka, India and Thailand — and even as far away as Port Elizabeth
in South Africa, some 8000 kilometres from the earthquake epicentre (see
fi gure 2.38). The US Geological Survey reported that as many as 283 000
people were killed, with 14 100 people still missing and over one million
left homeless.
Worst hit was the Sumatran city of Banda Aceh (see fi gure 2.39).
A 20-metre tsunami pushed a 3-metre wall of water, mud and debris a
distance of 10 kilometres inland from the coastline.
Tsunamis are giant sea waves produced when
water is displaced by underwater earthquakes,
landslides or volcanic eruption.
Tsunamis are giant sea waves produced when
water is displaced by underwater earthquakes,
landslides or volcanic eruption.
Amplitude is the height of a wave.Amplitude is the height of a wave.
Chapter One Life, the universe and everything 9
Figure 1.8:An imaginary reconstruction of an Archean scene about 3.5 billion years ago
There was no gaseous oxygen in the atmosphere at this stage. If we were
to travel back to that time, we would suffocate — if we didn’t get roasted
fi rst! One aspect of this lack of oxygen is that there would also have been
no ozone layer (the protective layer at the top of our atmosphere that
fi lters out most of the deadly UV radiation from the sun).As more gases accumulated in the atmosphere, the air pressure increased
and caused the water vapour in the atmosphere to condense into liquid rain. This water gathered in the natural basins that had formed in the Earth’s crust, creating the early oceans. Slowly, over millions of years, the water cycle was established (see fi gure 1.9). In this cycle, water from the oceans evaporates and rises to form clouds of water droplets. The clouds move over the land, where the droplets fall to the ground as rain. The rain forms watercourses that allow the water to fl ow back to the ocean, where the process continues.With the water cycle established, the carbon dioxide gas in the atmosphere was dissolved out of the atmos-phere by rain and entered the oceans, leaving nitrogen as the most common gas in the Earth’s atmosphere. Even today, nitrogen gas makes up 79 per cent of our air. So where did the oxygen come from?
Figure 1.9:The water cycle
#/.$%.3!4)/.AS�RAIN %6!0/2!4)/.
FROM�WATER�SURFACE
8 Science 21
Eye on the mediaWet Days in HellFollowing the news that the Hadean era of Earth’s evolution had a wet climate
and long, calm interludes (AS, June 2005, p. 11), it now appears that the
formation of continents at the time worked much as it does today.Last year Professor Mark Harrison of the Australian National University’s
Research School of Physical Sciences announced that zircons found in the
world’s oldest-known rocks indicated they had been formed in the presence of
water. This suggested that the early Earth had oceans much like today.The Hadean era was named after the ancient Greek underworld because this
period of intense asteroid bombardment was considered hellish, but Harrison’s
work suggests that most of the time the environment may have been quite
reasonable.
Further results obtained by Harrison suggest that the Earth was not a water
world at the time, with continents forming much as they have ever since.‘We have evidence that massive amounts of continental crust were produced
almost immediately upon the Earth’s formation,’ Harrison said. ‘The Hadean
Earth may have looked much like it does today rather than our imagined view
of a desiccated world devoid of continents.’Harrison’s conclusion is based on the ratio of two isotopes of hafnium, one
of which is formed by the radioactive decay of lutetium. The ratios found
suggest that a reservoir of lutetium and hafnium had appeared prior to the
formation of the zircons. Such reservoirs are consistent with modern continent
formation.
Harrison admits that the picture he is drawing is a radical contrast to the
perception most scientists hold of the early Earth. ‘But these ancient zircons
represent the only geological record we have for that period of Earth history,
and thus the stories they tell take precedence over myths that arose in the
absence of observational evidence,’ he says.Source: Australasian Science, January/February 2006, p. 5.Clarifi cation questions1. What evidence is mentioned in this article for the Earth having a wet climate
during the Hadean eon?2. How does the Hadean Earth described in this article differ from the present
theories about its appearance?3. On what basis does Harrison make his claims?4. When does Harrison believe the continents formed? How does this differ from
present theory?
The Archean eon (3900–2500 MYA)The main characteristic of the Archean eon was the formation of Earth’s
fi rst real atmosphere and the majority of the continental landmasses. The
early atmosphere seems to have been made up of water vapour, carbon
dioxide and nitrogen with small amounts of ammonia, carbon monoxide,
sulfur dioxide and hydrogen sulfi de. These gases were the product of the
volcanoes that covered the Earth’s surface. The release of these gases from
the interior of the planet is called volcanic outgassing.
Volcanic outgassing is the process by which gases are released into a planet’s atmosphere from its molten interior by volcanic activity.
Volcanic outgassing is the process by which gases are released into a planet’s atmosphere from its molten interior by volcanic activity.
FEATURES
• A focus question at the start of each chapter to introduce the context and guide scientific inquiry.
• Investigations and activities interspersed through chapters to allow students to process and practise the concepts presented in the text.
• Engaging content written at a reading level suitable for the audience.
• Key terms in the minor column, adjacent to where they are discussed in the text.
• Stimulus articles and images that show real-life applications of science.
• End of chapter questions.
• Special reference appendix to guide skill development in scientific investigation and research methods.
FREE POST this order form to PO Box 3065, Reply Paid, Stafford BC QLD 4053 FREE CALL 1800 777 474 FREE FAX 1800 802 258EMAIL [email protected] jacarandaplus HOTLINE 1800 JAC PLUS (1800 522 7587) EMAIL [email protected]
CONTACT JACARANDA
TRIAL COPY ORDER (please tick)
p Please send me my FREE 30 day trial* copy of Science 21 (9780731404193 RRP$67.95)
FIRM SALE ORDER
Please send me _________ copies FIRM SALEof Science 21 (9780731404193 RRP$67.95)
Chapter One Life, the universe and everything 105
The energy crisisEnergy comes in a variety of different forms, which you will probably remember from earlier science studies: kinetic, sound, electrical, chemical potential, elastic potential, gravitational potential, nuclear, and light energy. So many aspects of our modern way of living rely on our ability to convert energy from one form or another. Our cars move because the stored chemi-cal energy of the petrol is converted into kinetic energy. When we listen to music, we rely on the chemical potential energy of the batteries being converted into electrical energy, which eventually becomes sound energy. The electricity in our homes is converted into lighting so we can see, heat so we can cook, and kinetic energy so our clothes can be spun dry.
Just as energy comes in a variety of forms, it is also available from a variety of sources. Generally, we can describe these energy sources as either renewable or non-renewable energy sources.
Figure 4.1:The formation of fossil fuels
Figure 4.1:The formation of fossil fuels
Dense vegetation
SedimentsPeat
Sedimentary rocks
Coal
Slowly rotting plant material
Dense vegetation
SedimentsPeat
Sedimentary rocks
Coal
Slowly rotting plant material
At the beginning of the 21st century, the majority of Australia’s energy is being supplied by fossil fuels. Like the rest of the world, we face an energy crisis where there will simply not be enough fossil fuels to supply the ever-increasing demand for energy to power our homes, our vehicles and our industries. So what do we do when the fossil fuels run out? Could nuclear energy be the answer?
4
Nuclear energy — Australia’s energy future?
Providing your email address will ensure you receive the latest information and special offers from Jacaranda. Your information will not be passed onto any third party. If you do not wish to receive emails from Jacaranda please tick this box p* Within 30 days of receiving any TRIAL material, I agree to pay for the book/s or return it/them in mint condition to: Returns Dept, John Wiley & Sons Australia, Ltd, Reply Paid 77171, 33 WINDORAH ST, STAFFORD QLD 4053 This is a FREE POST address, so it costs
nothing to trial the material. All prices shown include GST. Prices and availability subject to change without notice 05/10. ABN 67 009 673 081
Our solutions to your teaching and learning challenges...
Students need to develop the capacity to communicate about science.
Interdisciplinary science course aims to develop in students a broad understanding of the relevant science for today’s scientific and technological age
Engage students with real science practice
a Each chapter is essentially a stand-alone module addressing a particular scientific aspect of the modern world in which students live.
a�Units are context-based with an inquiry focus, developing students’ ability to think scientifically.
a Investigations and Activities are included as a way of allowing students to experience hands-on science techniques or demonstrating scientific principles.
a�Discussion sections suggest topics for class consideration either in small groups or larger forums or debate.
a��End of chapter questions allow students to check their understanding of the basic principles.
Teaching & LearningChallenges Our Solutions
Science 21Science 21 is designed to address the exciting new course of the same name being implemented for senior science students in Queensland from 2011. The course takes an interdisciplinary approach to science that aims to produce scientifically literate young adults. Jacaranda’s Science 21 is underpinned by this approach, presenting units of study that have intrinsic interest to students who will live and work in the twenty-first century.
Kahni Burrows
Sign up to JacNews and receive the latest information and special offers direct to your inbox!Register today at www.jaconline.com.au/go/jacnews or include your email address overleaf.
