Answer:
Economic: Imperial governments, and/or private companies under those governments, sought ways to maximize profits. Economic expansion demanded cheap labor, access to or control of markets to sell or buy products, and natural resources such as precious metals and land; governments have met these demands by hook (tribute) or by crook (plunder). After the advent of the Industrial Revolution, dependent colonies often provided to European factories and markets the raw materials they needed to manufacture products. Imperial merchants often established trading posts and warehouses, created transportation infrastructure, and sought control over strategic choke points, such as the Suez Canal in Egypt (which allows boats to cut thousands of miles of travel time between Asia and Europe). Imperial powers often competed with each over for the best potential resources, markets, and trade.
Exploratory: Imperial nations or their citizens wanted to explore territory that was, to them, unknown. Sometimes they did this for the purpose of medical or scientific research. At other times, they did it for the sense of adventure. Invariably, imperial explorers sought to discover, map, and claim territory before their imperial competition did, partly for national and personal glory and partly to serve the imperialist goal of expansion.
Ethnocentric: Imperial nations sometimes believed that their cultural values or beliefs were superior to other nations or groups. Imperial conquest, they believed, would bring successful culture to inferior people. In the late 19th century, for example, European powers clung to the racist belief that inferior races should be conquered in order to “civilize” them. The Europeans acted on their ethnocentrism, the belief that one race or nation is superior to others.
Political: Patriotism and growing imperial power spurred countries to compete with others for supremacy. It’s a matter of national pride, prestige and security. Empires sought strategic territory to ensure access for their navies and armies around the world. The empire must be defended and, better yet, expanded. Political motives were often triggered as responses to perceived threats to the security or prestige of the imperial power or its citizens abroad.
Religious: During imperial expansion, religious people sometimes set out to convert new members of their religion and, thus, their empire. Christian missionaries from Europe, for example, established churches in conquered territories during the nineteenth century. In doing so, they also spread Western cultural values. Typically, missionaries spread the imperial nation’s language through educational and religious interactions, although some missionaries helped to preserve indigenous languages. British missionaries led the charge to stop the slave trade in the nineteenth century, while others, such as French missionaries in Vietnam during the same time period, clamored for their country to take over a nation.