How many kinds of mangoes are cultivated in India?

It is estimated that about a thousand varieties of mangoes are grown in various parts of India, each variety characterized by its own peculiar taste and flavor. The number of wild varieties is unknown. Of the cultivated kind, thirty varieties of are commercially well known. Some of them are the Duseheri or Dashehari; the Langra and the Chausa of the North; the Alphonso and the Kalepad of the west; the Baneshan (Bangan-Palli); the Jahangir (Umdra); the Imam Pasand and Neelum of the South and south-east; and the Gulab-Khan and the Malda of the east. Quite often one single variety assumes several different names as orchardists like to consider each seedling as a new ‘variety’ and to Christen it with exotic new name. One can call it by any name, but a mango is always delicious.
Although the mango is now cultivated in several countries of the world, no where else has it achieved the prime position it enjoys in India. It occupies about 70% of the total area under fruit cultivation in this country. The State of Uttar Pradesh has the largest area under mango cultivation where 150 varieties of mangoes are grown. Bihar comes next followed by Andhra Pradesh.

Another four elements

Helium

Helium is twice as heavy as hydrogen, but it is still only one seventh the weight of air. Unlike hydrogen does not burn, so it is used in modern airships.

Lithium
Lithium was discovered in 1817 by Swedish scientists Johan August Arfvedson. It takes its name from the Latin word for rock, although it is actually a metal. Lithium is so light (42 times lighter than the heaviest element, osmium) and so soft that it can be easily cut with a knife. It floats because it is half as heavy as water, and lighter than some types of wood. It is used to make lithium batteries.

Potassium and sodium
Both are discovered in 1807 by Sir Humphry Davy. Both are metals that are lighter than water. In a laboratory, potassium is usually kept in paraffin because if it comes into contact with water it releases hydrogen and generate so much heat that it catches fire.

1980s and 1990s

By 1981 the ARPA network had 213 hosts (sites to which users could connect). A new host was added approximately every 20 days. In 1982 a common language called TCP/IP was invented which allowed all internet computers to communicate with each other and the network was first called an internet. In the 19802s many more people and businesses began to use computers. The internet began to be used commercially, as well as by governments and universities.
In 1991 the World Wide Web (www) was created. It combined words, pictures and sounds in a system that ordinary people could easily understand and use. By 1994 approximately 40 million people were connected to the internet. They could exchange information, sell goods, and work form any computer with a phone call. The rolling stones rock group even broadcast a concert over the internet. Schools started using the internet as an electronic library. By 1996 users in almost 150 countries around the world were connected to the internet

The heaviest elements

Osmuim
Osmium is the heaviest element of all (22.61g per cubic centimeter). It was discovered by the British chemist Smithson Tennant in 1803. He named it after the Greek word for smell because it smelt bad. Osmium is twice as heavy as lead – so heavy that a cubic foot (0.028317 cubic meters) weighs 640ks, as much as ten average people! A football made of osmium would weigh 126 kg, or much as two adults. Osmium is also very hard, and is used to make hard-wearing points, such as the nibs of fountain pens.

Platinum
Platinum was used before anyone realized that it was an element. It weighs almost as much as osmium (21.45g per cubic centimeter) and is also used in catalytic converters in cars to reduce the pollution from exhaust gases.

Plutonium
Plutonium was discovered in 1941 and is heavy and highly radioactive metal. It is used as a nuclear fuel and in nuclear weapons - a kilogram of plutonium produces an explosion equivalent to 20,000 tonnes of TNT.

Elements on Earth

There is calcium in the Earth and sea in the form of calcium carbonate. Sodium exists in the form of sodium chloride, the salt in the sea and on our tables. The quantities of both calcium and sodium are so vast that these elements are considered unlimited. Some elements are mined and used in industry. Iron is the most common, followed by magnesium. There are quite small amounts of some precious metals on earth, which is why they are so valuable. For example, there are about one million tones of silver and 15,000 tonnes of gold. Elements are constantly being taken from Earth, but new discoveries are being made. We are still some way from running out of even the rarest elements. Element 98 was given the name Californium by the four scientists who discovered it in 1950. They were working at the University of California at Berkeley, and named the element for both the state and their university.

Which is the most ancient fruit of India?

The mango which has been under cultivation for over 4,000 years is the most ancient fruit of India. In the Ramayana and the Mahabharata, forests and gardens of mangoes have been mentioned. It is said that a mango grove was presented to the Buddha so that he could use it as a place of repose. Alexander the great is reported to have spotted a pleasant mango garden in the Indus Valley in 327 B.C. Besides being referred to in Sanskrit texts, the mango tree is prominently carved on stupas. And the fruit was a popular motif on the textiles of ancient India.
The mango probably originated in the Assam – Burma – Thailand region. Nature propagated it further in the tropical and sub-tropical forests of India. Today it is found throughout the country in wild and cultivated form.
Hailed as the “Golden Fruit” and ‘the choicest fruit of India’, the mango today is the most favorite fruit of every Indian, and has earned for itself the title ‘the King of Fruits’.

Colors of the stars

One star may have a spectrum that is like that of other stars. The stars in each spectral class are found to have the same color. The colors range from blue to red. Our sun is a yellow star, in the middle of the range. The temperature of a star can also be found by measuring colors in the spectrum. The blue stars are large, hot, and brilliant, with temperatures of 25,000 degrees or more. Red stars are rather cool and have surface temperatures of 1,600 degrees or less. To find what chemical elements are in the stars, the astronomer compares their spectra with spectra made in the laboratory. All the elements found in the stars are also present in the earth, but the stars are basically balls of very hot gas, mainly hydrogen and helium. The astronomers also use special types of telescopes which can photograph large areas of sky. Still another type of instrument is the radio telescope. This has a very large antenna, a receiver, and a registering meter.