Was the dominant strategy for improving worker productivity during the early 1900s?
Scientific management
America's increased prominence in International affairs, the New Deal and other programs that have expanded federal responsibility, and the president's increased visibility, due to the development of the mass media.
What resources were used in the 1900s and how did they help the kids learn?
The ruler, the switch and the paddle were tools of the trade for education professionals in that era. At least students learned silence, attention, respect and other virtues even if genius, creativity and inquiry were probably stilfed.