Zips are less than a hundred years old, and safe zips which did not burst open at embarrassing moments have only been around for sixty years. Before the zip, clothes and footwear had to be fastened by buttons, laces or hooks and eyes. Getting dressed was fiddly, time-consuming and likely to put you in a bad mood right at the start of the day. Then came the 'slide fastener', as the inventor of the first working zip called his brain wave. By today's standards it looks clumsy and crude. It was not very reliable either. But to Whitcomb L. Judson, the Chicago engineer who came up with the idea, it was a stroke of genius.
The first zips were designed to fasten boots and shoes. It is just as well they weren't intended for clothing because they came apart easily and tended to catch on things like socks or stockings. The real breakthrough came ten years after Judson's slide fastener. In 1913 a Swedish engineer named Gideon Sundback had the idea of making a zip from a pair of identical locking strips attached to a flexible backing. On each locking strip there are small teeth that hook with eyes under the teeth on the other strip. Try pushing a zip together with your fingers and you will find that the teeth are too wide to slot between the adjoining ones on the other side. When you use the slide though, the teeth are splayed open to let the ones opposite lock into place. Unless you are very unlucky, a zipped zip will stay firmly closed for as long as you want it to. When you unzip it the process is reversed and the slide splays the teeth open to let the ones opposite unlock and spread apart.
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There are several reasons why Friday has been considered the most unlucky day of the week. Jesus Christ was crucified on a Friday. Friday was traditionally the day when criminals were executed. According to one superstition, if you cut your nails on a Friday witches would pick up the pieces and turn you into a witch yourself. Friday was also known as 'Tip Tod's Day', meaning the Devil's day. In earlier times sailors didn't like put ting to sea on a Friday. And it was also said that work started on a Friday was never finished - which sounds like a good excuse for taking Friday easy.
Then there is thirteen. This has been an unlucky number in the Christian world ever since thirteen sat down to eat at the Last Supper on the night before Jesus Christ was crucified.
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Saturday, April 17. 2021
Penguins have adapted to life in the sea rather than in the air. They may not be able to fly and they may look clumsy when they waddle about on land, but in the water they are superb swimmers. In fact, penguins swimming and diving in the sea are so graceful they have been mistaken for dolphins or porpoises.
Penguins have wings, but they are short and stubby compared with the wings of birds that fly. Penguins' wings are stiff at the shoulder too. They do not have elbow joints either. So penguins cannot fold their wings like other birds. But these sturdy little wings make great paddles in the water, where penguins are really at home. They are also useful for helping the birds along on land when they are frightened or just in a hurry. You will see penguins flapping them furiously to get up a bit of speed. For most of their es, though, penguins are well equipped with the wings they have. In any case, flying wings would be useless to them underwater.
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