'Social Change' is such a general form that it can be, and often is, used to refer to almost any kind of change not qualified by some other term, such as economical or political change. Sociologists have led to work hard to limit this broad meaning in order to make the term more specific and hence useful for social theory. At the most basic level, social change refers to changes that are significant- that is, changes which alter the 'underlying the structure of an object or situation over a period of time' (Giddens 2005:42). Thus social change does not include any and all changes, but only big ones,changes which transform things fundamentally. The 'bigness' of change is measured by not only by how much change it brings about, but also by the scale of the change, that is, by how large a section of society it affects. In other words, changes have to be both intensive and extensive- have a big impact spread over a large sector of society - in order to qualify as social change.
           Even after this kind of specification, social change still remains a very broad term. Attempts to further qualify it usually try to classify it by its sources or causes; by its nature, or the kind of impact it has on society; and by its pace or speed.
          For example, evolution is the name given to a kind of change that takes place slowly over a long period of time. This term was made famous by the natural scientist Charles Darwin, who proposed a theory of how living organisms evolve- or change slowly over several centuries or even millenia, by adapting themselves to natural circumstances. Darwin's theory emphasized the idea of 'the survival of the fittest' only those life forms manage to survive who are best adapted to their environment; those that are unable to adapt or are too slow to do so die out in the long run. Darwin suggest that humans being evolved from sea-borne life forms(or varieties of fish) to land-based mammals, passing through various stages the highest of which were the various varieties of monkeys and chimpanzees until finally the homo sapiens or human form was evolved. Although Darwin's theory referred to natural processes, it was soon adapted to the social world and was termed 'social Darwinism' a theory that emphasized the importance of adaptive change. In contrast to evolutionary change, change that occurs comparatively quickly, even suddenly, is sometimes called 'revolutionary change'. It is used mainly in the political context, when the power structure of society changes very rapidly through the overthrow of a former ruling class or group by its challengers. Example include the French revolution (1789-93) and the Soviet or Russian revolution of 1917. But the term has also been used more generally to refer to sharp,sudden and total transformations of other kinds as well, such as in the phrase 'industrial revolution' or 'telecommunications revolution' , and so on.
           Types of changes that are identified by their nature or impact include structural change and changes in ideas, values and beliefs. Structural change refers to transformations in the structure of society, to its institutions or the rules by which these institutions are run. For example, the emergence of paper money as currency marked a major change in the organisation of financial markets and transactions. Until this change came about, most forms of currency involved precious metals like gold and silver. The value of the coin was directly linked to the value of the gold or silver it contained. By contrast, the value of paper currency note has no relationship to the value of the paper it is printed on, or the cost of its printing. The idea behind paper money was that a medium or means for facilitating the exchange of goods and services need not itself be intrinsically valuable. As long as it represents values convincingly-i.e., as long as it inspires trust - almost anything can function as money. This idea was the foundation for the credit market and helped change the structure of banking and finance. These changes in turn produced further changes in the organisation of economic life.
           Changes in values and beliefs can also lead to social change. For example, changes in the ideas and beliefs about children and childhood have brought about very important kinds of social change, there was a time when children were simply considered as small adults - there was no special concept of childhood as such, with its associated notions of what was right or wrong for children to do. As late as the 19th century for example, it was considered good and proper that children start to work as soon as they were able to. Children were often helping their families at work from the age of five or six; the early factory system depended on the labour of children. It was during the 19th and early 20th centuries that ideas about childhood as a special stage of life gained influence. It then became unthinkable for small children to be at work, and many countries passed laws banning child labour. At the same time, there emerged ideas about compulsory education, and children were supposed to be in school rather than at work, and many laws were passed for this as well. Although there are some industries in our country that even today depend on child labour at least partially(such as carpet weaving,small tea shops or restaurants, matchstick making, and so on), child labour is illegal and employers can be punished as criminals.
            But by far the most common way of classifying social change is by its causes or sources. Sometimes the causes are pre-classified into internal(or endogenous) and external(or exogenous) causes.There are five broad types of sources or causes of social change- environmental, technological economic,political and cultural.