The invention of the steam engine was the most significant economic and social change in the 1800's because it made traveling and shipping goods a lot easier and faster.
The steam engine was invented in 1698 by many people but the person that built the very first one was Peter Cooper. It was invented because it would make traveling and shipping good a lot faster and easier. Farmers could send their products far places with out them spoiling, this lead to more profits for farmers.
It affected people because they were able to travel places faster and visit different places and they were able to get products from different places. The country was able to ship good to many different places to sell for profits.
Both the north and south were affected by the steam engine because it created many other inventions that lead to minding the gap between the north and south. It affected westward expansion by making it able for people to go west by locomotives (trains) and steam boats to visit or live.
Sources; 1) http://railroadandsteamengine.weebly.com/impact.html "Effects of the Steam Engine" by Ahmed Guster written in 2012
2) http://sciencing.com/did-invention-steam-engine-change-way-people-worked-13612."how did the invention of the steam engine changed the way people work?"by Joseph Cummins written in 2017
3) http://www.explainthatstuff.com/steamengines.html "how steam engines work" By Marshall Brain written in 2017