Northern Society: A New Workforce -Immigrants also treated poorly in factories Low wages, long hours, harsh conditions, use of child labor -Most immigrants lived in overcrowded and unsanitary homes known as tenements -Labor Unions began to form and use strikes to improve conditions Most strikes were unsuccessful -Became known as wage slaves or slaves without a master When North criticized slavery, South condemned practices of northern factory owners In 1820, half of the nation's industrial workers were children under the age of 10.