Science by Email 7 October 2011

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	07 October 2011
The neutrino detector used in this experiment. News: Faster than the speed of light? By Patrick Mahony Physicists in Italy recently made a strange discovery. They were measuring the speed of particles called neutrinos in an underground laboratory. Neutrinos are subatomic particles created in some nuclear reactions. They have no electric charge and small mass, which means they can travel long distances, even through solid rock. The neutrinos in question were being made at CERN 730 kilometres away on the French–Swiss border. When they measured the amount of time it took the neutrinos to travel between the laboratories, they found the neutrinos were travelling 60 billionths of a second faster than the speed of light. According to Einstein’s theories, the speed of light is like a universal speed limit: nothing can travel faster. How do you even measure an interval of time that tiny? To measure an object’s speed, you need to measure two things very carefully: the distance an object has travelled, and the amount of time it took to get there. To measure the distance, the team in Italy needed to pinpoint the exact location of the neutrino detector, 1400 metres below the ground. To solve this problem, they closed off one lane of a highway tunnel for a week and used highly accurate GPS detectors to determine the exact location. To measure time they didn’t use a clock you’d find at home – they used caesium atomic clocks. Atomic clocks use the transitions of electrons within atoms to measure time. These clocks are so precise they can measure time intervals to within a billionth of a second. This is how the physicists were able to measure such a small difference in time. There is still some doubt as to whether the neutrinos are actually travelling faster than the speed of light. Other physicists will attempt the same experiment to see if they obtain a similar result. If the results are accurate, then the universe might need a new speed limit. More Information New Scientist: Faster-than-light neutrino claim bolstered How atomic clocks work Neutrinos: everything you need to know Careers Careers in physics
You'll need these materials.   Tie one end of the string to the key ring.   Put the keys on the floor. Cut the string so that it reaches from the floor to your armpit.   Tie the other end of the string to the metal ring or washer.   Hold the pen in one hand and use it to support the string so that the keys dangle over the edge.   Hold the metal ring in your other hand. Release the ring.   Try this: Key trick You will need String Keys on a key ring Scissors A metal ring or washer A pen What to do Tie one end of the string to the key ring. Put the keys on the floor. Cut the string so that it reaches from the floor to your armpit. Tie the other end of the string around the metal ring or washer. Hold the metal ring in one hand. Hold the pen in your other hand, and dangle the keys over the pen. Let go of the metal ring while holding onto the pen. What happens? What's happening? This activity is all about forces. There are a number of forces to take into account. The first is gravity. When you let got of the washer, gravity exerts a force that pulls everything (the keys, washer and the string) straight down towards the ground. Another force is the tension in the string. The keys and the washer pull against each other to create the tension. As the keys are heavier than the washer, there is a net force pulling the washer sideways. The combination of a sideways and downwards force on the washer means that its overall motion is angled towards the ground. The final force to consider is friction. Friction exists when substances rub against each other. There is friction between the string and the pen which causes the string to slow down. The combination of friction and the motion of the washer causes a rotation. The rotation causes the string to wrap around the pen. With each loop of string that wraps around the pen, the friction increases. Eventually the force due to friction is greater than that due to gravity, and the keys stop moving. Applications Friction has important applications. One common use is the brakes in a car. When the brake pedal is pushed, the brake pads apply friction to stop the wheels of the car moving. The braking systems of many vehicles including bicycles and trains also use friction to slow down. Friction converts kinetic (moving) energy into heat. You can observe this by rubbing your hands together to keep them warm. The faster the motion, the more friction and therefore the more heat is generated. In systems where there are fast moving parts, the heat from friction can cause large amounts of damage. An example of this is a spacecraft re-entering the Earth’s atmosphere. The craft moves so fast that friction with the air can cause enough heat for the craft to burn up. One way engineers address this problem is by building spacecraft out of materials that can withstand high temperatures. The amount of friction varies depending on the substance – rough substances create more friction than smooth substances. Many mechanical systems, including your car, use substances called lubricants to reduce the amount of friction. Try another Science by Email activity about friction More information Find out more about friction View online version Quiz questions 1. Maxwell’s equations are commonly used in: a) biology, b) geology, or c) physics? 2. In marine biology, what is a medusa? 3. What would you most likely do with anthracite? 4. Which of the following contains inorganic carbon: a) carbon dioxide, b) petrol, c) sugar, d) ethanol? 5. In information technology, what does WLAN stand for? Did you know? Around a third of the world’s fossil fuel emissions are absorbed by forests. CSIRO Ecosystem Sciences is conducting research to explore how forests can be used to reduce greenhouse gases in the atmosphere. Website Read it! Read about the winners of the 2011 Nobel Prize for Physics, including Australian National University Professor Brian Schmidt. Watch it! Learn more about the mysteries of lightning. Events National: Earth Science Week Earth Science Week is an international celebration promoting the importance of the geosciences to society. Earth Science Week 2011 will be held 9–15 October. The American Geological Institute has announced ‘Our ever-changing Earth’ as the theme for 2011 celebrations. Geoscience Australia in the ACT is holding a screening of the winners from its Geologi short film competition at 11.30 am on Tuesday 11 October, and displaying images from the Top Geoshot Photo Competition. More information and other events can be found at the Earth Science Week website. Aluminium, Saturday 8 October at 9.00 am on Network Ten This week’s episode of SCOPE stars the very shiny, very durable metal: aluminium! From smelting and recycling, to boat building and even a DIY electroscope – we have packed the episode with everything you need to know about this widely used element! So don’t get foiled and join Dr Rob as he once again proves that the ordinary really does become extraordinary under the SCOPE!    Next episodes: Thursday 13 October: Solids Liquids Gases Saturday 15 October: Floods 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. c) physics. Maxwell’s equations describe aspects of electricity and magnetism. 2. A medusa is the adult form of a jellyfish. 3. You would  burn anthracite – it’s a form of coal. 4. a) carbon dioxide. All the other substances contain organic carbon. As mentioned in last week’s Science by Email, it’s important to distinguish between organic and inorganic soil carbon in agriculture. The Australian Government’s Soil Carbon Research Program has researchers developing new methods to accurately measure carbon in soil. 5. WLAN stands for Wireless Local Area Network. The most popular way to connect computers without wires, the chip at the heart of this technology was invented by CSIRO scientists. 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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