1.       The main motive behind  imperialism is  the  economic  and  political  benefits  of  the  imperialist country with  or  without  gaining  political  control of  the  subordinate  state.  While under colonialism, the subordinate state is brought under the direct political control.

2.       Colonialism is one of the methods through which the idea of imperialism is practiced.

3.       Under  colonialism,  the  colonizers move  permanently to  the  new  territory  while  maintaining the allegiance to their home country. This may not be the case in imperialism.

4.       Colonialism can altogether  alter the social structure, physical structure and economics of a region.  In  the  long  term,  the  traits  of  the  conquered  are  influenced  by  the  conqueror.  For example, India’s political and cultural traits are influenced by British.

5.       Imperialism has a longer history than Colonialism. While the history of colonialism dates back to 15th century, Imperialism has its origins dating back to the Romans.

6.       Colonialism ceased to exist in the decades of 1950s & 60s, but imperialism took a new form i.e.  the  practice of  economic  exploitation  of  politically  independent  but  economically  less developed countries, which is still practiced.

Industrial revolution was the process of change from an agrarian and handicraft-based economy to  one  dominated  by  industry  and  machine  manufacturing.  It  began  in  Britain  in  the  18th century and from there spread to other parts of the world.

The factors that led to spread of colonialism after the advent of Industrial revolution included:

A.      Industrial revolution led to capitalist system of production where maximizing the profit was the main motive. It was done through low wages and high production. But low wages also meant low demand for  the  products  manufactured.  Thus,  capitalist  countries  started  to  find new markets  and  buyers for  their  products.  European  countries  found  markets  in  Asia  and Africa where industrial revolution had not occurred.

B.      In addition, the European markets needed new sources of raw materials. Europeans changed the  pattern  of  production  in  African  and  Asian  countries  and  grew  products  suited  for  factory use in the West.

C.       As industrial revolution helped create wealth in the European countries, the financial investors started  investing  surplus  money  in  new  colonies  where returns  were  guaranteed  by  the colonizers.

D.      Changes in transport and communication, which enabled steamships to carry goods between home  countries  in  Europe  and the  acquired  territories  in Asia and  Africa  much  faster  than  old sailing vessels. With cheap labour, imperialist countries built railroads and inland waterways in conquered  area  for  extraction  of  raw  materials  and  sale  of  their  manufactured  products  into new markets.