Why do the tides rise and fall?

The water in the oceans is held close to the earth by gravity. But the moon and sun also have some ‘ Pull’ on the earth. The moon’s gravity affects water in the oceans. The sea water is pulled slightly towards the moon. Causing the bulge or high tide. ON the opposite the sea water is pushed away, causing a second bulge. High tides occur twice in about 24 hours.

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What are the dark patches that the naked eye can see on the moon?

The dark patches are large plains on the moon, which reflect less sunlight than other parts.

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Why does the moon keep the same face towards the earth?

When it first formed, the moon was probably spinning rapidly. But the earth’s gravitational pull has showed it down. The moon now turns its axis in the same time that it takes to orbit around the earth. This means that the same face is all ways pointing inwards, towards the earth.

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Why do glaciers appear?

A glacier is like a great river of ice. Glaciers appear when more snow falls than melts every year. The snow collects, squeezing the lower layers hard. It turns to ice and forms a glacier. Glaciers appear only in cold climates where there is snow all year round. This is either in high latitude ( The Arctic or Antarctic) or at high altitudes. Glaciers often appear first on the shady side of a mountain.

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Why do eclipses of the moon occur?

The earths cast a long shadow in to the slpace, away from the Sun. If the moon passes through this shadow, it grows dim. This can happen onl on ‘full moon, . When it is opposite the sun. However, since the moon’s orbit is tilted, it usually passes to one side of the shadow.
The earth shadow is not really black, since some sunlight filters reddish into it and the eclipse moon can last for over one and a half hours, if the moon passes through the shadow’s center. There is a faint outer shadow or ‘Penumbra’ around the central ‘umbra’.

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Why is Venus (Planet) so hot?

The atmosphere of Venus is about 90 times as thick as our own planet, earth. This thick atmosphere acts like a blanket, holding in the heat, that is why, the mid-day temperature is 4800c . This is often call “Green house effect. Since the air inside a greenhouse heats up for the same reason. Moreover, the atmosphere of Venus contains a lot of carbon-di-oxide, a gas which holds in heat very well.

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What do clouds comprise of ?

Clouds are masses of tiny condensed water droplets or ice crystal. Warm air can hold a great deal of invisible moisture compares to cold air. When warm air-cools, moisture is condensed into visible droplets. Clouds come in a great many shapes and sizes and at a variety of height low clouds below 2500 meters are stratus, Stratocumulus, Nimbostratus, cumulus and Cumulonimbus, medium clouds are Altostratus and Altocumulus and high clouds i.e. above 6100 meters are cirrocumulus and cirrostratus.

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Why do we perspire before it rain?

Just before it rains the atmosphere gets saturated with water vapor. The perspiration exuded by us, therefore it does not evaporate quickly but remains on the surface of the skin. Hence, we feel the perspiration at that time.

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Why does grass gather more dew in the nights than stones and bricks?

Dew is easily formed on the objects, which are good radiators, bad conductors and are n close contact with the surface of the earth. Gasses and leaves are better radiators than stones and bricks. Hence, more dew is formed on grasses and leaves. Moreover, grass and leaves give out water constantly which appears in the form of dew because the air near them is saturated with water vapors.

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Why is it hotter in cloud-covered night than in clear night?

It is because clouds prevent the heat radiated by the earth from escaping into the sky. As this heat remains in the atmosphere, the cloudy nights are warmer in comparison to the clear nights.

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Why places near the sea are cooler in summer and warmer in winter than farther inland?

Because of its high specific heat, it takes longer far water to get heated up or to get cooled. During summer days, the land near the sea gets heated up quickly but the sea water remains cool and thus, cool breeze blowing from the sea reduces the heat in the adjoining land area. The reverse happens in winter. The land gets cooled quickly but the sea water remains warm and thus, the land gets warm breeze from the sea. But the land farther inside does not have this advantage. This account for the difference in the climatic conditions.

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