How did public schools in the 19th and 20th centuries uphold the "melting pot" notion of the United States?

Public schools were the space were children from all ethnic backgrounds shared a space.

Explanation:

In the late 19th century, and early 20th century, the United States received hundreds of thousands of emigrants from many parts of the world, specially from Europe, and public schools were the space where an important percentage of these students stayed for an important part of the day.

Like this, public schools worked as a place where American values, the Constitution, and the English language, were promoted among a very diverse population who could have otherwise formed cultural bubbles.

she went to newnham women's college at cambridge university