Science by Email 10 February 2012

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	10 February 2012
News: Opening a can of elephants By Patrick Mahony Is introducing elephants to Australia a good idea? Driving through northern Australia, what sort of animals would you expect to see? Perhaps kangaroos, crocodiles and water buffalo, but what about elephants? Or a Komodo dragon? Professor David Bowman from the University of Tasmania recently suggested introducing elephants into Australia’s northern grasslands to help fight invasive gamba grass. Gamba grass is an introduced weed that fuels bushfires but is too big for most herbivores to eat. David also suggested that introducing Komodo dragons could reduce populations of feral animals such as pigs and water buffalo. What do you think of David’s plans? On the one hand, Australia doesn’t have a good track record of introducing non-native species – just look at rabbits, cane toads and lantana. However, some current environmental management strategies are expensive and not working, so changes may be necessary. Scientists' ideas can be controversial. Galileo, Charles Darwin and Albert Einstein supported radical ideas that were criticised and condemned at the time but are now accepted by mainstream thinking. However, other ideas have fallen by the wayside due to lack of evidence. Ask yourself some questions: what are the benefits of David’s suggestion? What could go wrong? Are there consequences that we haven’t thought of yet? How could scientists monitor and control such a course of action? Is all of this worth it? More information Bring elephants to Australia? CSIRO link: Biosecurity and invasive species Gamba grass Careers link Good Universities Guide: Environmental studies
Try this: Make your own shadow puppets You will need these materials.   Draw outlines for your puppets on the cardboard and cut out with the scissors.   Tape the puppets to a wooden skewer.   Set up the lamp on a table, and shine onto the whiteboard or wall. Make the room darker.   Place your puppet between the lamp and the wall or whiteboard. Move it to make shadows of different sizes.     You will need Lamp Cardboard Tape Pen or pencil Scissors Wooden skewers Blank wall or whiteboard What to do Draw outlines for your puppets onto the cardboard. You might want to make people, or your favourite animals. Cut out the puppets using the scissors. Attach a wooden skewer to the back of each puppet using tape. Set up the lamp on a table and point it at the wall or whiteboard. Turn on the lamp then make the rest of the room dark by turning off other lights and closing the blinds if necessary. Hold your puppets close to the lamp (not touching) and look at the shadow on the wall. Try moving the puppets closer and further away from the lamp, without touching the lamp. What do you notice happens to the shadow? What’s happening? Light can be thought to travel as a wave. It radiates outwards from the light bulb in the lamp, a bit like ripples in a pond. If we place an opaque object, such as a cardboard shadow puppet, in the path of the light, we block the light waves from travelling past. By placing the shadow puppet close to the light source, a higher proportion of the light waves are blocked. This results in a larger shadow being cast on the wall. Moving the puppet further away from lamp results in a smaller shadow as fewer light waves are blocked. Applications Shadows are all around us and can sometimes be spectacular. A solar eclipse occurs when the Moon passes between the Sun and the Earth, casting its shadow on the Earth below. Not all the Earth is cast into darkness though, the shadow the Moon casts depends on the positions of the Sun, Moon and Earth. By Patrick Mahony Try another Science by Email activity using light and shadows More information How light works CSIRO link: What is a solar eclipse? View the online version Quiz questions 1. What colour is water vapour? 2. Which element is more common in the Earth’s crust: platinum or gold? 3. What sort of animals use baleen in their mouths to feed? 4. Who led the first Australian Antarctic expedition? 5. Is GJ 667Cc a star, a planet or a comet? Did you know? Posidonia oceanica is a species of seagrass that can clone itself. Research from the University of Western Australia Oceans Institute found examples of a single organism of Posidonia stretching up to 15 kilometres wide. Websites Hear it! Scientists have recreated the song of 165 million year old crickets. See it! See the winners of the 2011 International Science and Engineering Visualization Challenge! 2012 BHP Billiton Science Awards The BHP Billiton Science Awards recognise young people who have completed practical research projects that use innovative approaches and scientific procedure to address real world problems. There are also awards for teachers that make outstanding contributions to science education. The winners for 2012 were announced in Melbourne this week. Full details of the winners can be found on the Awards website. Information on the 2013 Awards can be found here. Structures, Sunday 12 February at 7.30 am on Network Ten On this episode of SCOPE find out all of the science behind the materials, design and construction of structures! Tune in as Dr Rob puts on his hard hat and once again proves that the ordinary becomes extraordinary, under the SCOPE. Next episodes: Thursday 16 February: Coast Sunday 19 February: Elements Want to have your own episodes of SCOPE to watch whenever you feel like it? Click here to download them directly into your iTunes folder, or go here to download iTunes. Charges apply. Quiz answers 1. Water vapour is colourless. 2. Platinum is more common than gold in the Earth’s crust. 3. Some species of whales use baleen to feed. 4. Douglas Mawson led the first Australian Antarctic expedition. 5. GJ 667Cc is a planet located about 22 light years from Earth that may contain water. Science by Email is a CSIRO publication. The Department of Agriculture, Fisheries and Forestry and bankmecu are proud partners of Science by Email. Editor: Jasmine Leong | Manage your subscription | FAQ

 

 

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