History Next: Review Sheet Up: No Title Previous: Homework Assignments A Ridiculously Brief History of Electricity and Magnetism Mostly from E. A History of the Theories of Aether and Electricity... 900 BC - Magnus, a Greek shepherd, walks across a field of black stones which pull the iron nails out of his sandals and the iron tip from his shepherd's staff (authenticity not guaranteed). 600 BC - Thales of Miletos rubs amber ( elektron in Greek) with cat fur and picks up bits of feathers. 1269 - Petrus Peregrinus of Picardy, Italy, discovers that natural spherical magnets (lodestones) align needles with lines of longitude pointing between two pole positions on the stone. 1600 - William Gilbert, court physician to Queen Elizabeth, discovers that the earth is a giant magnet just like one of the stones of Peregrinus, explaining how compasses work. ca. 1620 - Niccolo Cabeo discovers that electricity can be repulsive as well as attractive. 1816 - David Brewster invents the kaleidoscope. for long wires.
Evolution speeding up as population grows: scientists Updated Tue 11 Dec 2007, 11:41am AEDT US researchers say human evolution has been moving at breakneck speed in the past several thousand years, far from plodding along as some scientists had thought. In fact, people today are genetically more different from people living 5,000 years ago than those humans were different from the Neanderthals who vanished 30,000 years ago, according to anthropologist John Hawks of the University of Wisconsin. The researchers say many of the recent genetic changes reflect differences in the human diet brought on by agriculture, as well as resistance to epidemic diseases that became mass killers following the growth of human civilisations. For example, Africans have new genes providing resistance to malaria. In Europeans, there is a gene that makes them better able to digest milk as adults. "The central finding is that human evolution is happening very fast, faster than any of us thought," Mr Harpending said. - Reuters
Fibres could generate electricity from body motion ‘Power dressing’ could take on an entirely new meaning thanks to novel energy-scavenging textile fibres created by researchers at the Georgia Institute of Technology in the US. They claim that a pair of trousers worn by a hiker or a tent fluttering in the breeze could generate enough electricity to charge a mobile phone, if they were made from fabric woven from the fibres. The fibres consist of millions of 100 nm-diameter zinc oxide nanowires grown on the surface of much larger Kevlar strands. The nanowires are about 3.5 µm long and radiate outwards from the surface of the Kevlar, which can then be twisted together to create thicker fibres and ultimately woven to make a durable fabric. Piezoelectric material When such a fabric is stretched, crumpled or otherwise disturbed, the nanowires would rub against each other and bend. Twisted pair To prove that they could do this, the team coated one Kevlar-nanowire strand with gold and twisted it around a second bare Kevlar-nanowire strand.