What was the greatest economic motive behind nineteenth century colonization

During the Nineteenth-century colonization, European nations undergone the scientific revolution. It enable them to mass produce a certain goods like never before at a much faster rate.
This process require a lot of raw materials.
In order to seek cheap source of these materials, the European countries invested in journey to seek for new lands that potentially possess abundance of natural resources. This was the reason why they started colonizing weaker countries.