In the late 1800s, most kids were working to support their family because wages were low. They worked in extremely hazardous environments.
Children would sometimes work full time to support their family. This resulted in kids being uneducated.
Because kids wouldn't complain to salary cuts, and had tiny hands that were perfect for handling machine parts, they were preferred over adults. This resulted in many adults being unemployed.
In 1908, Lewis Hine took pictures of children working in hazardous environments. He traveled 50,000 miles in a year to document these photos and showed it to the leader of the National Child Labor Commitee.
After ten years of photographing and 5,000 pictures, Hine couldn't take pictures anymore because he was broke. Later, in 1938, the Fair Labor Standards Act was signed by President Roosevelt, outlawing child labor. This allowed man children the chance to finally go to school.