Why the 1920s in America was considered the "modern era" and "modernism."

QUESTIONS FROM INSTRUCTOR:. Many historians cite the 1920s as the decade in which America entered the "modern era." Given the myriad labels attached to this decade, this essay focuses on the broader context of all those movements under the umbrella term "modernism."
First, what is modernism and why did it apply to the 1920s (as opposed to earlier decades)? What ideologies or beliefs had changed by the 1920s that qualified this decade as "modern" for America?
Second, to expand on those changes, what new issues/events/movements did Americans face in the 1920s? Discuss at least three exampl…