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later, Summerford retired and moved to Vancouver, ow it is formed—how clouds build up the electrical Canada. charges that produce it—is still a matter of debate, In 1924, while fishing from a riverbank, Summerford was owever. Within a thunderstorm, there are powerful struck by lightning again. More specifically, the lightning | updrafts and downdrafts which occur often and close struck the tree (presumably a fallen one) that he was ogether. While the updrafts are busy carrying small water sitting under. The injury caused paralysis in the right side droplets to heights between 35,000 and 70,000 feet, of his body. Eventually, though, he regained the ability to | downdrafts are transporting hail and ice from the frozen walk. He was again struck by lightning in the summer of upper parts of the storm. These particles collide, causing 1930, while taking a stroll in a local park. When a he water droplets to freeze and release heat, which then lightning strike issues from a clear blue sky, as it didin affects the surface of the hail and ice, resulting in the this instance, it is known as "a bolt from the blue". We are _ production of a soft hail, called "graupel". told that the injury rendered Summerford permanently An electrostatic process occurs when this graupe paralysed, and that he died a couple of years later. The collides with additional water droplets and ice particles. final touch to this amazing story of coincidence is that, | As negatively charged electrons are sheared off the rising about four years later, lightning struck the cemetery at particles and collect on the falling particles, the end which Summerford was buried, product is a storm cloud that is destroying his tomb. negatively charged at its base and If Sullivan or Summerford had lived positively charged at the top. These during the time of ancient Greece, they regions, one being positively charged probably would have been regarded as and the other being negatively charged, ane A special relationship with we On those spots are a tracted to cach other The unter ods. ople may have ught, . . apar ey are, the stronger the perhaps, that they ‘were enemies of where lightning attraction they ave for each other and Zeus, the king of the gods and the god was observed to the greater the electric field between of the sky and thunder. On those spots . . them. The atmosphere—an extremely where lightning was observed to strike, strike, the ancient good insulator that inhibits electric believing such lations to be touched Greeks built leaking. so to spesk The charge gete by the gods and therefore holy. When temples, believing greater and greater until suddenly it someone was killed by lightning, * overpowers the atmosphere's owever, their body would be left such locations insulating properties and a current unburied, for it was considered to be touched of electricity ores a path through unwise to mess with the work of a he air until it makes a connection god. by the gods and with something. The current is therefore holy. discharged as a lightning strike. Cloud-to-ground lightning occurs when, beneath the storm, positive charges pooled within the surface of the earth shadow the storm wherever it goes. A stepped leader, ground, between clouds or within which is a channel of negative clouds. The word "electrostatic" charge invisible to the eye, shoots relates to static electricity. As distinct from a current, down to the ground in a forked pattern. Attracted to a which moves along the wires in a circuit, for example, a streamer, which is a channel of positive charge reaching static charge is exactly that: static; it doesn't move. Iftwo up from the ground—usually through something tall, such objects, one with a positive static charge and the other as tree, house or telephone pole—the two connect and a with a negative static charge, are placed close together, powerful electric current begins flowing. What we observe they'll adhere to each other because positive attracts _ as lightning is actually one or more return strikes as the negative. When we receive a static "shock", such as by current makes its way back towards the cloud. When the touching a metal doorhandle, it means that the built-up process rapidly repeats itself along the same path, this charge has been suddenly neutralised by a discharge. __ results in a flicker of lightning. Because lightning heats up This may result in a spark and a crackling sound, though he surrounding air to around 20,000°C—about three A massive electrostatic discharge Ancient superstitions aside, lightning is basically a massive electrostatic discharge which can take place between a cloud and the of course, if the charge happens to bleed off to ground, no imes the Sun's surface temperature—two things occur. such shock will occur. First, a bright flash is caused by iridescence. Second, As well as in thunderstorms, lightning can occur in here is a clap of thunder—a shockwave created by the volcanic eruptions, forest fires and even dust storms. The — sudden expansion of air. They occur in this order because conditions needed to create lightning are known. Exactly ight travels faster than sound. On those spots where lightning was observed to strike, the ancient Greeks built temples, believing such locations by the gods and therefore holy. NEXUS ¢ 53 to be touched FEBRUARY - MARCH 2010 www.nexusmagazine.com