Scientific Phenomena: Green Leaf Appears Green in Daylight, Animals, Mammals and Birds

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Scientific Phenomena

A Green Leaf Appears Green in Daylight but Looks Dark in Red Light. Why is It So?

During daylight, a green leaf appears green because out of all the constituents of white light, it reflects green only, all other colours being absorbed. But when red light falls on it, it is all absorbed and hence the green leaf reflects none and looks dark.

Why the Outer Surface of a Glass Containing Iced Water Becomes Wet?

A tumbler containing cold water cools the air near it so that a film of moisture is deposited on the outside of the tumbler by the condensation of water vapours present in the air.

A Solar Eclipse Can Occur Only on a New Moon Day. Why?

Soloar eclipse is due to the full moon coming in between the sun and the earth, and hence it is natural that it should be a new moon day.

Why the Lunar Eclipse Occurs Only at Full Moon but Not Every Full Moon?

The lunar eclipse occurs only when the moon is full and is near to one of its nodes which does not occur every full moon.

Where Days and Nights Are Equal Throughout the Year and Why?

Day and nights are equal throughout the year at the Equator. During the course of the earth’s revolution round the sun, one half of the Equator is always in the light and the other half is in the dark. i.e., the circle of illumination always cuts the Equator into equal parts.

What is the Difference between a Star and a Planet?

Star is the name given to a fixed celestial body which has its own light whereas Planet is the name given to a celestial body which revolves round the sun in elliptical (regular oval shape) orbit. A planet has no light of its own, but it reflects light of the sun.

Where Days and Nights Are Longer in the Year?

Longest day: 21st June. Longest night 22nd December (in Northern hemisphere).

Why Are Mountains Cooler Than Plains?

Because (i) the air of the mountains is rarer than that of the plains and contains fewer dust particles. The air on the mountains absorbs less heat than the air on the plains, (ii) the heat absorbed during the day on the mountains radiates very quickly at night owing to the rarity of the air and nights on the mountains are cooler, (iii) due to uneven surface of the mountains, the major portion always remains in the shade. The sun does not heat much of the land which may heat the air.

Animals, Mammals and Birds

  • Albatross: Sea birds, North Pacific, off the American coast. Also found in Antarctica

  • Alpaca: Animal found in Chile (South America)

  • Apes: These are four kinds of apes in the world, two in Africa: Gorilla and the Chimpanzee, and two in Asia: Gibbon and the Orang - Utan.

  • Beaver: Found in Europe (Russia and Poland) and North America. It is a genus of mammals of the Rodentia order with short scaly ears and webbed hind feet and broad flat muscular tail. Its skin is of considerable commercial value. It is noted for ingenuity and industry in building houses and damming shallow streams. It is also valued for its reddish-brown fur and a secretion costoreum (Caster oil) used in medicines and perfumes.

  • Camel: Found in deserts of Arabia and India. It has long legs with padded feet, a long neck with a hump on its back. Its hump is made up of fat and is a store- house for food. It can also store water in the stomach and can go for days without a drink. It is also called “Ship of the Desert”.

  • Chameleon: It is a family of lizards. The common chameleon is a native of Africa. Chameleon is remarkable for its power of changing colour to resemble its surroundings when surprised a power that is due to the presence of pigment bearing cells beneath the skin. It is slow in movement.

  • Cheetah: Found in India and Africa. Fastest land animal at short run

  • Corals: Small marine animals closely related to sea- anemone, found mainly in the Mediterranean; also found in the Indian Ocean.

  • Crocodiles: can be recognised by their narrow snouts which have a notch near the front on both sides. They live mostly in the tropics along the sides of rivers and lakes. Alligators also resemble the crocodile but have broader snouts.

  • Dinosaurs: They are great reptiles flourished about 150 million years ago in the Jurassic period. It was over 24 m long and must have weighed some 30,000 kilograms. Its tiny head contained a brain no larger than a hen’s egg. It was clumsy and slow-moving and probably quite harmless.

  • Elephant: Found in Africa and India. It is the largest existing quadruped. Both males and females have large ivory tusk of considerable commercial value. The Indian elephant is domesticated and can carry up to 2,000 lbs. on long journeys maintaining a pace of about 6 km per hour.

  • Emu: Running bird of Australia. It is the largest of living birds after the Ostrich.

  • Giraffe: Found in Africa and South Sahara except in the Congo forests. It is the tallest of existing animals.

  • Ilama: A dwarf camel-like animal found in South America. It has no hump but has a long neck and is used as a beast of burden.

  • Kangaroo: Is a pouched (Marsupial) mammal of Australia. It can reach a height of over 6 ft. It is the national animal of Australia.

  • Kiwi: Flightless bird, found in New Zealand, now very rare. It is little larger than a domestic hen and lays astonishingly large eggs for their size. Its feathers are hair-like, and it has rudimentary wings concealed by the plumage.

  • Koala: Animal found in Australia.

  • Ladybird: It is an insect usually of a red or yellow colour with small coloured or black spots.

  • Lion: Among the big cats, the lions live in open grass- land, its tawny coat blending with the dry bush. It is lazy in habit; Gir forest is familiar in India.

  • Mustang: Animal found in American prairies

  • Nightingale: A singing bird found in India.

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