Science by Email 21 October 2011

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	21 October 2011
Classical music sounds complex but is highly compressible. Other genres of music sound simple but aren't as compressible. News: What makes a musical masterpiece? By Patrick Mahony Why are the works of Mozart often considered to be masterpieces, but those of modern pop musicians aren’t? CSIRO scientist Dr Nick Hudson thinks he might have the answer: compressibility. Compression is a concept used in information theory. At its heart lies the concept that the size of a data set can be reduced (‘compressed’), and then used to recreate the original. Compression is used all the time in computers and communications: photos are often reduced in size so they can be emailed faster and music files can be compressed so more songs can be stored on a device. Compressibility is the measure of how much the data can be compressed without losing so much information that the original can’t be recreated. Things that are highly ordered or have high levels of symmetry are more compressible than those that don’t. For example, if you know that a person’s face is symmetrical, you only need to see half their face and you can recreate the original. Nick’s idea is that music considered ‘beautiful’, such as classical music, has a higher degree of compressibility than other genres of music such as pop. He took audio files of examples of several genres of music and measured how much he could compress them. He found that classical music was more compressible than the other genres studied. Why should compressible music be considered more beautiful than music that isn’t? Nick thinks it’s because humans understand the world through patterns. Classical music sounds complex, but its compressibility means it’s simpler for our brains. Pop music sounds simple, but is actually quite complex. Our brains detect the patterns in the music even if our ears don’t and this could be why it is considered ‘beautiful’. Of course, the concept of beauty is highly subjective, but all the music Nick analysed displayed more compressibility than white noise. This research highlights the role of patterns in music and throws a new perspective on why music is enjoyed around the world. More Information How file compression works The Music Instinct: Science and Song Careers University of New South Wales: Music science
You'll need these materials.   Inflate and deflate two balloons a few times each.   To each bottle add 2 tsp dried yeast, 2 tsp sugar and 125 mL water.   To the bottle labelled 'bleach' add 2 tsp bleach.   Place a balloon over the mouth of each bottle. Leave bottles in a warm area for 30 minutes.   Try this: Bleached yeast Warning: This activity uses chemicals. Read any safety instructions, do not consume the chemicals used and wash your hands after completing the activity. See the CSIRO Education safety page for more information. You will need Dried yeast 2 x 600 mL PET bottles Bleach Sugar Balloons Water Measuring cups and spoons Marker What to do Label one bottle ‘control’ and the other ‘bleach’. Inflate and deflate two balloons a few times each. In each bottle, place 2 tsp dried yeast and 2 tsp sugar. Add 125 mL (1/2 cup) of warm water to each bottle. Add 2 tsp bleach to the bottle labelled ‘bleach’. Quickly place a balloon over the mouth of each bottle. Place the two bottles in a warm place for 30 minutes. After 30 minutes, compare the two balloons. What do you notice? What's happening? Yeast are microscopic fungi and they feed on the sugar in the water. They produce carbon dioxide gas as they break down the sugar to get the energy they need to grow. In the ‘control’ bottle, the gas builds up and inflates the balloon. Bleach contains a chemical called sodium hypochlorite in solution. In water, sodium hypochlorite becomes hypochlorous acid and some ions. The hypochlorous acid attacks the proteins of the yeast cells, killing the yeast in the process. As the yeast cells die, they no longer produce carbon dioxide and the balloon does not inflate as much as the control. Applications Bleach kills many different types of microbes including bacteria and viruses, not just yeast. Bleach has long been used as a disinfectant because of this property. It is commonly used in places such as hospitals for sterilisation and in some places it is used to disinfect drinking water – but don’t try this at home! Bleach is not the only commonly used disinfectant. Other chemicals that aren’t as harmful to humans are used in products such as soaps and cleaners.       Try another Science by Email activity about yeast More information How stuff works: chlorine bleach How bleach kills bacteria View online version Quiz questions 1. Raman, atomic absorption and infrared are all types of what? 2. Where in your body would you find keratin? 3. Name the three most abundant elements in the Earth’s crust, by mass. 4. True or False: the Universe is expanding and the expansion is decelerating. 5. Approximately what fraction of the world’s mammals are bats? Did you know? A battery is a device that uses a chemical reaction to produce electricity. Researchers from CSIRO Energy Technology have developed the UltraBattery for use in low emission transport. Website See it! Take a closer look at some animal eyes photographed by scientist Suren Manvelyan. Read it! Learn about the science behind music. Big machines, Saturday 22 October at 9.00 am on Network Ten This week on SCOPE we are giving you a guided tour of some ultra-important, mega-awesome big machines! We get behind the wheel of some huge mining trucks, head down to the docks to see how big ships are made and Dr Rob is on location checking out the Air Force fire truck! So don’t forget to truck in when the ordinary becomes extraordinary, under the SCOPE!    Next episodes: Thursday 27 October: Animation Saturday 29 October: Weird animals 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. Raman, atomic absorption and infrared are all types of spectroscopy, which is the study of the interaction of matter and radiated energy. 2. You would find keratin in your skin, hair and nails. 3. Oxygen, silicon and aluminium are the three most abundant elements in the Earth’s crust. 4. False. The Universe is expanding, but the expansion is accelerating. 5. Approximately one quarter of the world’s mammals are bats. Research conducted by the Australian Museum investigated the life cycle of the grey-headed flying fox in Australian urban areas. 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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