Science by Email 23 December 2011

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	23 December 2011
Photosynthesis provides plants with food, but one day could provide even more. News: Fuelling the future with photosynthesis By Patrick Mahony Photosynthesis is the process where plants use light energy to make their food. It is important for the planet in many ways. For example, through this process carbon dioxide is converted into oxygen. Could this fundamental process also have other environmental benefits? Researchers have modified photosynthesis to produce hydrogen gas. In regular photosynthesis, light energy is used to energise electrons. The electrons are then passed along transport chains to an enzyme which combines a hydrogen ion and chemical to produce a compound used to make plant food. The scientists replaced that enzyme with hydrogenase. Instead of using the electrons to make plant food, hydrogenase combines electrons with hydrogen ions to produce hydrogen gas. Why is hydrogen gas useful? It could be used as an alternative fuel source. Fossil fuels such as petrol and coal produce the greenhouse gas carbon dioxide when they combust, as well as other pollutants such as particulates. When hydrogen combusts with oxygen they produce water vapour. This mix doesn't produce the other pollutants of fossil fuels, so it is a cleaner form of energy. More information ABC Science: Souped up photosynthesis produces H2 How does photosynthesis work? Careers Biochemical Society: What is biochemistry?
You will need these materials.   Dissolve 3 tablespoons of copper sulfate in 2 cups of warm water.   Place the stickers on the hinge and submerge in the solution for 30 minutes.   Put on some gloves, remove the hinge and clean with toothpaste and a cloth.   Dip the hinge in the solution again, this time for one minute. Remove and allow to dry.   You now have your own copper-plated ornament!   Try this: Electro-ornament Safety: This activity involves chemicals. See the CSIRO Education safety page for more information. You will need Copper sulfate, available from gardening stores Zinc-plated hinge Water Jar Star stickers Latex gloves Measuring spoon Measuring cup Cloth Toothpaste What to do Place 3 tablespoons of copper sulfate into the jar. Add 2 cups of warm water to the jar and stir until it dissolves. Place a few stickers onto the zinc-plated hinge. Submerge the hinge in the copper sulfate solution for 30 minutes. Put on a pair of rubber gloves and remove the hinge from the solution. Rinse it with water. Using the cloth and a small amount of toothpaste, polish the surface of the metal until it is clean. Be careful not to remove the stickers. Rinse the hinge with water. Dip the hinge back into the solution for one minute. Remove it from the solution and rinse it with water. Allow the hinge to dry. Remove the stickers. You now have your own copper-plated ornament! What's happening? In this activity there are many metals to consider: steel (which is mostly made of iron), zinc and copper. The hinge is made of steel and covered in a thin layer of zinc. At the start of the activity, there isn't any copper metal but there are blue copper ions in the solution. Some metals lose their surrounding electrons more easily than others. Of the three metals involved in this activity, zinc loses its electrons most easily, followed by steel then copper. When the hinge is dipped in the solution, the zinc loses its electrons which react with the copper ions in solution. The products of this reaction are zinc ions and copper metal, which plates out on the hinge. The reaction can be represented as follows: Zn(s) → Zn2+(aq) + 2e- Cu2+(aq) + 2e- → Cu(s) When you remove and clean the hinge, the copper layer comes away quite easily, leaving the steel exposed. The second time you dip the hinge in the solution, a similar reaction occurs, although this time it is the iron in the steel which forms ions. The first reaction happens slower than the second. This is because zinc is a passivating metal. This means the zinc reacts with oxygen in the air to form a layer of zinc oxide which protects the metal beneath. It takes time for the copper ions to work their way through to react with the zinc. While the more reactive zinc is present, the copper ions will react with it instead of the iron. When you remove the outer layer between the dips, you remove the protective zinc coating. In the second dip, the copper ions will react with the exposed steel leaving a shiny, copper coating. Applications These reactions are examples of redox reactions. Redox reactions have important applications, a major one being batteries. Batteries use different metals and an electrolyte to produce electrical energy. Plating one metal with another is a common procedure. Examples include chrome plating of steels in cars; zinc plating of screws, nuts and bolts; and gold plating of jewellery. Try another Science by Email activity involving electroplating More information How stuff works: electroplating By Patrick Mahony View online version Quiz questions 1. Minke, fin and blue are all species of what? 2. Which of the following is not considered to be a greenhouse gas: a) nitrogen, b) carbon dioxide, c) water vapour, d) nitrous oxide? 3. What colour is malachite? 4. Researchers recently reported observing empathic behaviour in which non-primate mammal? 5. The Higgs boson is a theoretical particle believed to give rise to which property of matter? Final Science by Email for 2011 What do Trojan asteroids, one-clawed dinosaurs, wallaby milk and nanobots all have in common? They are the subjects of some of the weird and wonderful stories from Science by Email this year, and we can't wait to bring you more.                                   This is the last issue of Science by Email for 2011. We hope you've enjoyed reading the stories, doing the activities and the quiz as much as we have! Have a happy and safe Christmas, and we'll see you when Science by Email returns on 6 January 2012! Did you know? Researchers from the Australian National University have identified regions of Mars that could support microbial life. Website Read it! Sometimes scientific breakthroughs happen by accident. Read this list of ten accidental inventions. Do it! Check out these beautiful images demonstrating the physics of fluids. Elements, Saturday 24 December at 9.00 am on Network Ten Every science classroom has one, but who, how and why was the periodic table of elements created? And what on Earth is an element anyway? What's so special about iron, neon, calcium, tungsten, magnesium and chromium? Well for starters, they all feature on this episode of SCOPE! Join Dr Rob as he takes aim at the periodic table and scopes out all the science behind elements, once again proving that the ordinary becomes extraordinary, under the SCOPE. Next episodes: Thursday 29 December: Motion Saturday 31 December: New Year's science 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. Minke, fin and blue are all species of whale. 2. a). Nitrogen is not considered to be a greenhouse gas. 3. Malachite is green. 4. Rats were recently reported as displaying empathic behaviour. 5. The Higgs boson is believed to give particles their mass. Scientists at CERN have released results from the Large Hadron Collider that may be the first experimental evidence of the Higgs boson. 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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