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.

How was the light – year discovered?

We know that just by studying the spectrum an astronomer can tell you what a star billions of miles away is made of and the elements present, take the star’s temperature, figure out how fast it is moving, and whether that motion is toward earth or away from it! The spectrum consists of the lines into which white light is broken up when it is bent, as when it goes through a prism. All across the spectrum, in addition to the shadings of color, there are hundreds of parallel lines. They are known as Fraunhofer lines, in honor of their discoverer. Each chemical element in a gaseous or vapor state has its own pattern of lines occupying its own place in the spectrum. The lines stand for the colors taken up from the light by the element when it is heated so that it glows. This means that a scientist can find out what materials are present in any substance, no matter how far removed.

What is an Observatory?

Thousands of years ago, astronomers probably used the pyramids in Egypt and the towers and temples in Babylonia to help them study the sun, moon and stars. There were no telescopes then. In time, astronomical instruments were developed, and as they became larger and more numerous, observatories were built to house them. Some observatories were built to house them. Some observatories were built more than a thousand years ago. An observatory has to be built in the right place, a place with favorable weather conditions, moderate temperatures many days of sunshine and nights without clouds, and as little haze, rain and snow as possible. It must also be away from city lights and neon signs, which make the sky too light for good observation. There are buildings which include living quarters in addition to telescopes. The instruments are housed in structures of steel and concrete. The building for the telescope is constructed in two parts. The lower part is stationary, and the upper part, or roof, is in the shape of a dome which can be rotated.

What is an element?

The elements are sometimes called the building blocks of the Universe because everything in the Universe – including ourselves – is made of them. The nucleus of each element consists of atoms with the same number of protons. Each element is unique, although elements can exist in different forms – for example, carbon may be soft graphite or hard diamond. Elements cannot be broken down into any other substance. There is about 118 elements altogether, and 91 occur naturally on Earth. Others can be created artificially in laboratories, but in minute quantities and they have very short life spans of only thousandths of a second. Each element is also known by a one- or two- letter symbol as well as its name. Examples are Fe for Iron and Na for sodium. A chemical compound is a combination of two or more elements linked together, which can be broken down again into their constituent parts but no further.