Moon some facts

Moon

The moon ,the only satellite of the earth, moves from  west to east round the earth in 27 days ,7 hours and 43 minutes(sidereal month).

The same face of moon is always seen from the earth as the moon always has the same period of rotation and revolution. The moon has no light of its own. The changing position of moon in relation to the earth and the sun are known as different phases of the moon.

On full moon days the full face of moon, illuminated by sunlight, is visible from the earth when the earth lies between the sun and the moon.

On new moon days, the moon lies between the earth and the sun and therefore it seems dark from the earth.

From new moon to full moon period the moon  waxes and from full moon to new moon  period it wanes.

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Radio Carbon Dating

Radio Carbon Dating

Radio carbon dating or carbon dating

It is method for determining the age of an object containing organic material by using the properties of Radiocarbon C-14, a radioactive isotope of carbon.

This method was developed by Willard Libby in the late 1940 s. Libby received the noble prize for his work in 1960.

Principle:-

The Radiocarbon C-14 dating method is based on the fact that radiocarbon is constantly being created in atmosphere by the interaction of cosmic rays with atmospheric nitrogen.

The resulting Radiocarbon  C-14 combines with atmospheric oxygen to form radioactive carbon dioxide, which is incorporated into plant by the process of photosynthesis. Animal then acquire C-14 by eating the plant ,C-14 go into animal through food chain.

When the plant or animal die  it stops exchanging carbon with the environment or by food chain, and from that point of time Radiocarbon C-14  in the plant and animal body start decaying. And then the amount of C-14 begins to reduce as the isotope undergoes radioactive decay.

Measuring the amount of  c-14 in sample from dead plant or animal such as piece of wood or fragment of  bone provides information that can be used to calculate when the plant and animal died

So carbon dating is used to find out age of fossils.

process in flow chart:-

# HISTORY

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