Category Science

What are the magical qualities of garlic?

          Man has been using garlic since ancient times to add flavour to food. Garlic has a powerful smell and a pungent taste. The Roman soldiers believed that it helped them in being more courageous and stronger so they made it a point to include it in their regular diet. In the Middle Ages garlic was eaten as a defence against the plague. It was also worn on the body to ward off evil spirits.

          It is only a few years ago that man discovered its medicinal importance. Its bulb contains an antibiotic called allium.

          It has antiseptic properties and is used for curing intestinal disorders. It is highly effective in controlling high blood pressure. It is also being used as an effective remedy for heart ailments and cough.

          Some people crush it and rub it on the skin as a cure against insect bites and stings. Some people make syrup out of it and drink it to cure cold. Gardeners put garlic in the soil around peach trees, to discourage borer from entering and damaging the trees.

          Garlic plant is native to Europe and Asia but it also grows wild in Italy and Southern France. Garlic produces two types of bulbs or bulbets. The aerial bulbets produced on the flower stalk are used as seeds to new plants. It is grown as an annual crop. The underground bulbs, called cloves, are the one sold in shops. They are formed at the base of the plant much like an onion. One bulb encloses up to 20 bulbets. Garlic contains about 0.1% essential oil, the principal components of which are diallyl disulfide, diallyl trisul-fide and allyl propyl disulfide.

What is a flying fox?

          The flying fox is not really a fox, but a large, fruit-eating bat. There are 175 species of flying fox, and unlike most bats they have large eyes and long muzzles. It is their fox-like face that led to the name ‘flying fox’. They fly at dusk in search of fruit, relying mainly on sight and smell to find their way. Flying foxes are found in Asia, Africa, Australia and the islands of the Pacific.

          Most bats are small in size and look like mice. They are insect-eaters. Their wing-span is rarely as much as 30 cm. The biggest of all bats are the fruit eaters or flying foxes. One bat – the Kalong or Malay fruit bat has a wing-span of 1.5 metres. They have long sharp teeth with which they can even break a coconut. They weigh up to 1.5 kg. Unlike other bats, flying-foxes have well developed eyes which enable them to find their way by sight and not by sound waves. Their love for fruit makes them nuisance for orchards. Flying foxes live in thickly populated areas and make their homes in trees, resting close to a suitable source of food.

          Bats fly like birds, yet, in fact, they are mammals. They are the only mammals that can truly be said to fly. Their wings do not have feathers, but are made of a thin sheet of skin stretched between the long ‘finger’ bones. In most bats the wings are also joined to the legs and tail. Other ‘flying’ mammals, such as the flying squirrels can only glide, but the bats actually fly.

Do plants also breathe?

          All living beings breathe in order to survive. In the process of breathing they inhale oxygen and exhale carbon dioxide. Oxygen combines with hydrocarbons to produce energy and carbon dioxide.

          Plants are living beings and they also breathe to survive. The only difference between animals and plants, in this regard, is that while the animals inhale oxygen and exhale carbon dioxide, the plants inhale carbon dioxide and exhale oxygen during the day and inhale oxygen and exhale carbon dioxide at night.

          The leaves of plants take in carbon dioxide from the air during the day. A green substance called chlorophyll, that is present in the leaves, converts it into sugar and water. This process is known as ‘photosynthesis’ and it takes place only in the presence of sunlight. The oxygen produced in this process is discharged into the atmosphere and sugar is used up as food by the plants. This sugar gets converted into carbohydrates, carbonic acid and vitamins.

          During the night, when there is no sunlight, the process of photosynthesis comes to an end, during this period plants make use of some part of the sugar produced in the daytime. They take in oxygen from the atmosphere and give out carbon dioxide that is why it is not advisable to sleep under a tree in the night.

 

Why do some animals chew their cud?

          Animals like cow, buffalo, sheep, goat and camel have the habit of swallowing their food first and later bringing it back into the mouth to chew it at leisure. Such animals are called ‘ruminants’ or cud-chewing animals.

          Thousands of years ago, these animals could not protect themselves against their aggressive enemies like the lion and the tiger. In order to survive, they would swallow their food quickly without chewing it and run to a safe place where they would chew their food at leisure. But what makes such a strange process possible?

          The cud-chewing animals have a peculiar digestive system. Their stomach has four compartments — (1) Paunch or rumen (2) Reticulum or honeycomb bag (3) Omasum or manyplies and (4) Abomasum or the true stomach.

           When the animals swallow food, it goes into the first chamber. This is the largest of the four compartments. At this stage food is in the form of coarse pellet, i.e. the un-chewed portion of food. In this compartment it is softened and moistened. From here it goes to the second compartment, here it is converted into small pieces of convenient sizes called ‘cud’. At the time of chewing, the cud comes back to the mouth through a process called ‘regurgitation’. After it is chewed it goes into the third compartment. From here it passes on to the stomach where digestion takes place. Unlike other ruminants, camels do not have the third compartment.

           Cows, sheep and goats do not have any teeth in the upper jaw. Instead, the gums form a tough pad. So, with the help of the lower teeth and this pad these animals graze and take in food. 

 

Is there life on other planets?

          Earth is perhaps the only planet in the solar system where life exists. This is because the conditions favourable for the existence of life are available only on the Earth. Conditions present in other planets make life almost impossible.

          Mercury is the planet closest to the Sun. It is difficult to see it even with a powerful telescope. It does not have any atmosphere. The temperature during the daytime may even go beyond 400°C. The lack of oxygen and the extreme temperature make life on Mercury impossible.

          Venus, which comes next in terms of closeness to the Sun, is often described as the sister planet of the Earth. Venus and the Earth are almost identical in size, mass and density. Its diameter is 0.95 times and mass is 0.815 times as compared to the mass and diameter of the Earth. It is surrounded by thick clouds of carbon dioxide (95%). The temperature on its surface is about 95 times more (480°C) than that on the Earth. This makes Venus the hottest planet in the solar system. Under these conditions life is not possible here.

           Mars comes after the Earth and is much colder than the Earth. Its average temperature is about – 62°C. At night it may drop to – 101°C. It has an atmosphere much thinner than that of the Earth. It has been found that it contains 1 to 2% argon, 2 to 3% nitrogen, 95% carbon dioxide and 0.3% oxygen. These conditions suggest the possibility of existence of life on it but so far no traces have been detected.

          All other planets beyond Mars (Jupiter, Saturn, Uranus, Neptune and Pluto) are farther away from the Sun. The surface temperature of these planets is so low that no living organism can survive there. Besides, their atmospheres contain gases like methane and ammonia which are not favourable to the evolution of living organisms.

          Thus our Earth is the only known planet in the solar system where life exists. 

Why do snakes shed their skins?

          Snakes are long reptiles, having no legs. They probably evolved from a group of lizards that took up a burrowing way of life. Snakes are cold-blooded animals and are found in all parts of the world. They move along by wriggling their bodies. There are over 2400 kinds of snakes all over the world. Snakes have dry, smooth skin which they shed regularly.

          In fact all animals, including human beings, shed their skin due to natural wear and tear. Slithering (sliding or slipping) along the ground tends to wear out the skin of the snake, so it replaces it with a new one from time to time.

          The new skin grows underneath the skin and when it is fully formed, a fluid is secreted between the two to keep them apart and lubricated. The fluid behind the transparent eye scale clouds the eye and prevents the snake from seeing for a few days. It hides away and then splits the old skin at its lips by rubbing its head. The old skin is turned inside out as the snake wriggles out.