Why did the North and the South slowly begin to drift apart, and how did this eventually result in the Civil War?

The Industrial Revolution brought great change to the Northern states. People began living in cities and working in industrial settings. The South, however, continued to support most of its economy through agriculture. With its change in economy, the North no longer needed slave labor. The morality of slavery began to be questioned in the North, and some areas became free of slaves. In contrast, the South was dependent on the cheap labor slavery provided and believed that ending slavery would decimate their economy.
There was also a divide between the North and South as to the power of the federal government. The Southern states felt that state laws should supersede any federal mandates. Because of the growing nation and the addition of new states, the South struggled to keep power as additional “free” states were added to the Union. The loss of power in the South along with the debate over slavery eventually led the South to secede from the Union.