Category Science

What is an anticyclone?

The name anticyclone was first introduced by sir Francis Galton, the English meteorologist, in 1861 to describe weather conditions opposite to those of a cyclone. Anticyclones are characterized by fine weather and weak winds.

      In weather maps and climatic chances anticyclones appear as a region in which the pressure is higher than n its surroundings. So when the weather forecaster starts to talk about anticyclones you can be prepared for the weather to remain stable for some time, usually sunny and with occasional light rain.

      In a cyclone or low-pressure area the winds circulate anticlockwise in the northern hemisphere and clockwise in the southern hemisphere. Cyclones are usually areas of strong, violent winds and indicate bad weather.

Why do some plants capture insects?

 

 

           Some plants capture insects and other tiny animals and use them as food. They do not devour their prey by chewing but decompose them in a mixture of enzymes. The pitcher plant attracts an insect to its large showy leaf by means of sweet-smelling nectar. The leaf has a treacherous lip which precipitates the unwary victim into a deep hollow pitcher full of digestive “broth”, which soon decomposes its body. Other plants, like the Venus’s flytrap, snap their leaves shut on their prey as it prowls about the trigger hairs glistening with drops of nectar. The sundews secrete a sticky fluid.

Where does a leech feed?

      Leeches, which are rather slimy worms and vary in length from an inch to several inches, have two suckers, a big one at the rear and a smaller one at the mouth end. They have powerful muscles which enable them to expand and contract their bodies.

      This makes them excellent swimmers. They can also use their suckers to crawl on the land in tropical Asia, the island of the Pacific and the Indian Ocean, there is a particularly vicious and dreaded species of land leech which enters the breathing passages of animals, gorges on the animal’s blood and swells so that it cannot escape.

     Aquatic or water leeches cling to fishes, turtles and shell fish. Some leeches feed on earthworms and frogs’ eggs. Others live on the larvae of insects and even on the microscopic life on the floor of the pond.

     Leeches have been used in medicine from early times until quite recently to draw blood from a patient.

What is a loofah?

A loofah is a fibrous, cylinder-shaped vegetable product often used in bathrooms as a kind of rough sponge or gentle brush. It is the dries interior of the fruit of a plant known to botanists as Luffa aegyptiaca. Less dignified, though more descriptive, names for this tropical climbing or trailing herb are dishcloth gourd and vegetable gourd.

     The Luffa belongs to the great gourd family of plants, and its 800 relations include the cucumber, the melon and the pumpkin. In spite of having an unpleasant smell, the Luffa is cultivated in Egypt (hence the second part of its Latin name) and in Arabia, India and china. The yellow-flowered climbers can sometimes be seen adorning the trunks of palm trees. Besides being used to make loofahs, the luffa’s fruit is eaten in curry.

     The development of man-made materials has led to a decline in the loofah’s popularity, but many people still use its slightly abrasive qualities to stimulate the skin.

Where does the breadfruit tree grow?

      The breadfruit tree is found in the South Pacific Islands and, to a lesser, degree, in other parts of the tropics. It is an extremely handsome tree, growing up to 60 feet high. The oval leaves are a pleasant, glossy green and quite large.

      There are two distinct forms of breadfruit, one seedless and the other containing many seeds which, when boiled or roasted, taste much like chestnuts.

   The breadfruit, which contains a considerable amount of starch, is not really a fruit in the popular sense and is rarely eaten raw. It can be boiled or baked, served with salt, butter or syrup, and even sliced and fried like potatoes.

Why yews are often found in churchyards?

     Yews have long been associated with religious worship. So it is likely that churches were originally built near the sacred trees rather than the other way round.

     These trees live longer than any other species in Europe and can grow to an enormous size. Many are thought to be well over 1,000years old. Yews were revered by the druids of ancient Britain, France and Irelands and no doubt early Christian missionaries preached in the shelter of the trees before their first churches were built. Hywel Dda Howell the Good a Welsh king, who reigned in the 10th century, set a special value on “consecrated yews”.

   Some yews are even older than the ancient churches beside them, suggesting that the church was built on a spot already devoted to worship. The association continued, and it became traditional for yews to be planted in church yards.

    Also the great age to which yews live caused them to be regarded as a symbol of immortality and, therefore, associated with death, as man only becomes immortal after he dies.