Science by Email 6 January 2012

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	06 January 2012
An artist's impression of the GRAIL craft mapping the Moon's gravity. News: Lunar GRAIL quest By Patrick Mahony Planets and moons aren’t perfect spheres. Not only are they slightly fatter at the equator, deep craters, mountains and other geological features can affect the gravity at different spots on the surface. Two spacecraft are on their way to orbit our planet’s biggest satellite, one after the other. Their mission is to study the Moon’s gravity in greater detail than ever before. Called the Gravity Recovery and Interior Laboratory (GRAIL for short), the pair of spacecraft began their lunar mission on 31 December and 1 January. They will constantly send radio wave signals to each other at precisely timed intervals as they orbit the Moon. When one of the GRAIL craft passes over a mountain or crater, the small change in gravity will alter its orbit slightly. This changes the time it takes its radio signals to be detected by its partner. The GRAIL craft are equipped with instruments that can detect changes to the orbit of a few microns – about the size of a red blood cell. More importantly, by mapping the Moon’s gravity, scientists will not only have a clearer picture of its surface, but also what lies beneath. They hope to answer some questions about what is going on in the Moon’s interior, such as the size and composition of its mantle and core. The Moon is our nearest neighbour, but there is still a lot we can learn. Hopefully the GRAIL mission will provide some answers to these lunar mysteries. More information NASA's Twin GRAIL Spacecraft Reunite in Lunar Orbit Why a gravity map of the Moon? Careers How to become an astronomer Correction: In the News story ‘Fuelling the future with photosynthesis’ on 23 December 2011, we incorrectly stated that ‘through this process carbon dioxide is converted into oxygen’. The oxygen produced in photosynthesis comes from water molecules while the carbon dioxide is used to make sugars.
You will need these materials.   Place a coin into a balloon.   Inflate the balloon and tie the end.   Spin the balloon until the coin rolls on its side along the inside of the balloon. Repeat using different coins and a metal nut.   Try this: Singing balloon   You will need Balloons Coins of different value (for example, five cents, ten cents, one dollar, etc.) Metal nut What to do Place a coin into a balloon. Inflate the balloon and tie the end. Hold the end of the balloon between your index and middle finger and spin the balloon quickly. Keep spinning until the coin starts rolling on its side along the inside of the balloon – you can tell this is happening as the coin stops rattling around. Stop spinning and listen carefully. What do you hear? Repeat a few more times, using a different coin or nut each time. Is there a difference? What's happening? If you look at the edge of a coin you will see that it is not perfectly smooth – it has little notches on it. When the coin rolls around the inside of the balloon these notches make the coin bounce slightly as it rolls. The bounces cause vibrations in the balloon. The vibrations are transferred to the air which we hear as a high-pitched sound. The coins have different sizes and patterns of notches which produce different vibrations. We hear these differences in vibrations as variations in the pitch and volume of the sound produced. Applications Musical instruments use vibrations to create their sound. For example, violins and guitars use strings, a drum uses a membrane, and flutes and clarinets use columns of air to produce vibrations which we hear as sound. The same note played on a violin and a trumpet sound different. The different shapes and materials of instruments create slight differences in the sound which our ears are able to detect. Try another noisy Science by Email activity More information Science of sound By Patrick Mahony View online version Quiz questions 1. What two elements make up a benzene molecule?     2. Electric potential is measured in what unit? 3. Where is your mandible? 4. Scientists have developed a system based on photosynthesis to produce what sort of fuel instead of oxygen? 5. What is the main component of eggshell? Did you know? According to recent research of fossil fish, species’ heads evolve before other parts of the body. Website Read it! Read poetry from some of history's most famous scientists. See it! Sand as you’ve never seen it before! Bacteria, Sunday 8 January at 7.30 am on Network Ten Bacteria: just hearing the word may make your skin crawl. In fact, bacteria are actually crawling all over your skin. But do they deserve their bad reputation? Join Dr Rob as he divides, multiplies and SCOPES out all the science behind bacteria, once again proving that the ordinary becomes extraordinary, under the SCOPE. Next episodes: Thursday 12 January: Green science Sunday 15 January: Security 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. Carbon and hydrogen are the two elements that make up a benzene molecule. 2. Electric potential is measured in volts. 3. You would find your mandible in your skull – it’s your lower jaw bone. 4. Scientists used a system based on photosynthesis to produce hydrogen. 5. The main component of eggshell is calcium carbonate. Researchers from Murdoch University have developed a technique that uses eggshell DNA to reveal information about the evolution and behaviour of birds. Science by Email is a CSIRO publication. The Department of Agriculture, Fisheries and Forestry and bankmecu are proud partners of Science By Email. Editor: Mike McRae | Manage your subscription | FAQ

 

 

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