Good, bad and unexpected of Military life.
Know Spot: The Pantanal is the world’s largest swamp, covering a gargantuan area of 150,000 sq km, That’s greater than the total surface area of England. Much of the Pantanal (Spanish for marshland) is found in south-western Brazil but it streches into Bollovia and Paraguay too.
1. What is the thinnest material ever made?
That accolade goes to graphene, a form of carbon: sheets of it are only one atom thick. A very familiar form of carbon is graphite. If you were to peel those away layer by layer, you’d end up with a trace hust an atom thick. And that’s graphene.First produced in 2004, graphene has been found to have remarkable properties of strength and electrical conductivity,. The latter is causing the most excitement allows super efficient transistors. These in turn can be bundled into low-power, fast computer chips. Or, combined with graphene’s impressive strength, semi-conducting materials can be fashioned into thin, durable, efficient touchscreen displays for mobile phones.
Graphene is still an experimental material, but it is causing a real stir, winning the Nobel prize in physics for its discoverers in 2010. Expect it in a gadget near you recently.
2. Can you fire a gun in space?
Bullets carry their own oxidising agent in the explosive of the cartridge (which is sealed, anyway) so there’s no need for atmospheric oxygen to ignite the propellant. Without the stabilising effect of the atmosphere, the wide temperature variations in space might be a problem. Direct sunlight might make the gun hot enough for the ammunition to explode spontaneously whereas a gun kept in the shade would eventually become so cold that the primer in the firing cap might not go off at all. At very low temperatures, metals also become brittle and can stick together, which might cause the moving parts to jam.
3. Why do celestial bodies have the same shape?
Large celestial bodies such as planets and stars are spherical. This is because two forces, one of them gravity, are balancing each other. In stars, the gravity which tries to compress the star, is balanced by the thermal pressure acting outwards. In planets, the gravity is balanced by matter’s natural resistance to compression. In both cases, the two forces are in equilibrium and so the object takes on the most compact shape possible – a sphere.
Content Courtesy:BBC Knowledge Magazine
4. Why does a bee die after it stings you?
Worker honeybees have barbed stings that are evolved for stinging other bees and insects. It’s only when stinging mammals, with their thicker skin, that barbs become wedged. In trying to get free, the bee rips away part of its abdomen and dies after a few minutes later. Queen honeybees ans almost all other species of bee and wasp have smooth stings and can sting multiple times.