Describe as to how the age of fossils of plant and animals etc. is determined.

The method most commonly used, now, for estimating the age of fossils is radio-carbon dating. Radioactive isotope of carbon is commonly known as carbon- 14. Since carbon- 14 is chemically the same as ordinary carbon, both arc absorbed by plant and animal tissues in the same proportion as they arc present in the atmosphere as carbon dioxide. Plants use this carbon dioxide in making their food. Animals eat the plants. Hence, the proportion of carbon-14 in the tissues o f plants and animals is the same as in the atmosphere, as long as the plant or the animal is living. But as soon as it dies, no more carbon can enter its body as photosynthesis or food intake stops. Following death, the carbon-14, already present in the body, decays steadily into ordinary carbon. So the smaller the number of carbon-14 atoms remaining, the older is the fossil. This technique has been applied to materials of known age, and thus its accuracy was tested giving confidence in the age determinations of unknown samples. The carbon-14 method is applicable only to organic materials which still contain carbon. It cannot be used for fossils in which all organic matter has decayed. In that case the age of the fossil can be estimated by determining the presence of other radioactive elements like fluorine, or phosphorus.

Explain briefly the theory of chemical evolution and its scientific basis.

To understand the problem of origin of life, one must have a knowledge of the origin of 'organic molecules' on the earth. In the early stages of its development, with the hot gases condensing and molten matter which was solidifying to form what are rocks, today, the Earth acted as the huge factory, producing many kinds of compounds. The sources of energy available for the formation of numerous type of molecules were cosmic rays, ultraviolet radiations, electrical discharges such as lightning, radioactivity, and heat from volcanoes and hot springs. Molecules of all sorts were being continuously created and destroyed due to their state of agitation. The lighter gases of the atmosphere such as hydrogen, helium, oxygen, nitrogen, etc.. . Again, nitrogen, hydrogen and oxygen combined together to form ammonium nitrate. Compounds of carbon and hydrogen were also formed sometimes along with nitrogen or oxygen. These compounds are, today, called "organic compounds”. The Earth had at the same time started cooling down. As the Earth cooled sufficiently, torrential and prolonged rains were caused due to condensation of steam. This allowed living organisms to come to the surface of water and to survive even on land, if they got thrown out of the swirling and splashing water. The oxygenation of Earth's atmosphere was very significant from biological point of view, as organisms of greater complexity and even intel!igence could eventually arise.

Discuss the impact of freedom movement on the development of science and technology in pre-independent India.

By the early twentieth century, the Indian society had started witnessing the first stirrings for freedom from colonial rule. While their political aspirations led to a demand for self-rule, the frustration resulting from economic stranglehold found expression in their insistence on using only goods made in India. Swadeshi Movement provided further impetus for :

promotion of education along national lines and under national control with special reference to science and technology, industrialization of the country. In 1904, an Association for the Advancement of Scientific and Industrial Education of Indians was formed. The objed was to send qualified students to Europe, America and Japan for

studying science-based industries.

As mentioned earlier, in colonial India the environment was not conducive to higher studies, much less to research. Indians were allowed only. subordinate posts and even those who had distinguished themselves abroad were given less salary than the Europeans of the same grade and rank. This 'apartheid' in science made the Indians react strongly. J.C. Bose, the first noted Indian physicist, refused to accept this reduced salary for three years. Not only this, till the Royal Society recognized Bose, the college authorities refused him any research facility and considered his work as purely private. J.C. Bose was unorthodox in one more sense. He was one of the first among the modem scientists to take to interdisciplinary research. He started as a physicist but his interest in electrical responses took him to plant physiology." Whether it be education, agriculture or mining, the Congress touched several problems under its wide sweep.

Explain two differences between astronomy and astrology. Discuss why astrology cannot be considered to be a science.

our ancestors watched the Sun and the stars, and from their movements predicted the changes in season and the timing of floods. They could also relate the ocean tides to the Moon's apparent changes of shape. There were planets too in the sky. Only five of them could be seen-Mercury, Venus, Mars, Jupiter and Saturn. If the Sun'could

bring summer and winter, and the Moon move the oceans, why would the planets not have power over earthly affairs? Out of this wrong, but natural conviction grew astrology. The idea started developing that a person's future was determined by which constellations the planets were in at the moment of his or her birth. The motion of the planets was believed to determine the fates of kings, dynasties and empires. Astrologers studied the motion of planets accurately. Thus, astrology grew into a strange combination of observations and mathematics, with illogical thinking. Nevertheless, with time, astrologers came to be patronized by the State. This led to an increase in the influence of 'astrology, which continues to this day all over the world. But a precise cause and effect relationship between the movements of planets and human beings has never been scientifically established. In fact a critical analysis of astrological beliefs would show you that they re totally unscientific; they can be disproved in the light of the day to day events.

Name two incidents that have created a great deal of interest in the planets Mars and Jupiter, respectively.

Mars

After Venus, Mars is our closest neighbour. It seems very earth-like. There are ice-caps on its poles, drifting white clouds and raging dust storms in its atmosphere. Seasonally changing patterns occur on its red surface. There are large dark areas on its surface called maria (meaning 'seas'). It even has a twenty-four-hour day. Mars experiences summer and winter seasons, each of which lasts for almost six earth mkths. However, the planet's distance from the Sun causes these seasonal changes to be more extreme. It is tempting to think of Mars as an inhabited world. In 1877, the Italian astronomer, Schiaparelli, observed an intricate network of single and double lines crisis-crossing the bright arps of the planet Mars. He gave them the name of canali. Canali in Italian means channels or erooves. But it was promptly translated into English as 'canals'.

Jupiter

The most outstanding feature on t h s~ur face of Jupiter is the Great Ked Spot . It is a long oval area which is so huge that two earths. side by side, could be dropped through it. Sometimes it becomes pale plnk in colour and at other times a fiery orange red. For long, the Great Red Spot puzzled the astronomers. Th e Pioneer and Voyager missions to Jupiter revealed that the Red Spot is a huge cyclonic disturbance in the atmosphere. Jupiter is mainly a quick-spinning ball of gas and liquid with no solid surface. It also emits radio waves. Its composition, size and the number of moons gave rise to the idea that Jupiter is not a planet but rather a star with a "sdar system" of its own, that did not start 'burning'. It is estimated that if Jupiter,were just ten times heavier, it could have started to produce its own energy like the Sun