Kids Questions & Answers

Kids Questions & Answers

Tidal waves occur at night due to the moon’s attraction. Though the moon is present in the day too, why are there no tidal waves?

It is not true that there are no tidal waves during the day. Tidal waves are the result of the gravitational pull of the moon and the sun, but the effect of the sun is much less than that of the moon. In fact, tidal waves occur twice on any day-night cycle of 24 hours — once when the moon …

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The first explorers

In about 1500 B.C., Queen Hatshepsut of Egypt sent a fleet to the ‘Land of Punt’. No-one is sure where Punt was, but experts think the Egyptian sailors ventured out of the Mediterranean and sailed south along the coast of Africa. Astonishing voyages were also made by Arab and Chinese explorers. People from Asia reached Australia 25,000 years ago, by …

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Tape or disc-what’s best in video?

With video, you decide what to watch, you can use your television set to provide you with the films, shows, music-virtually any visual entertainment or information-of your choice. There are two systems: videotape recorders and videodisc players, each with their own particular advantages. Videotape and videocassette recorders play tapes and you can record television programmes on them as well as …

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Sunsets appear reddish why?

In the evening, the setting sun appears like a beautiful crimson red ball. But we all know it has not changed its color. Sunlight contains all colors. But the atmosphere on, around and over the earth contains molecules of water, vapour, dust, air and other impurities. The sunlight which passes through these media gets scattered. Our atmosphere scatters blue, violet …

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Skylab and spacelab-what’s the difference?

These are both laboratories that fly in space. Skylab was an American space station that contained much scientific equipment. It was used in 1973 and 1974. Spacelab is the name of a series of space laboratories taken into space by the space shuttle. Astronauts aboard the shuttle use them to do scientific experiments in space.

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Of all metals, why does mercury have the lowest melting point?

A metallic bond is characterized by free electrons and generally forms a specific geometric pattern of compact arrangement of atoms. All metals (except mercury) thus exist in a solid state at room temperature and have a specific crystal structure. Mercury belongs to the zinc group of elements in the periodic table, which comprises zinc, cadmium and mercury. They all have …

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Millions of people wear spectacles but how did they develop?

Although some Ancient Roman writers made reference to eyeglasses of beryl gemstone worn by the Emperor Nero, the earliest framed lenses to correct defects in vision were made in China in the 10th century. They did not appear in Europe until the later 13th century and are first recorded in Britain in 1326. These early spectacles were held in the …

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