Second Industrial Revolution in mid-late 19th century and early 20th century did make great changes in many nations such as United States of America (USA). In this era, the widespread use of steel had been shown in railroads, bridges, and infrastructures. Petroleum was also introduced within this time. Chemicals were also introduced in many fields such as fertilizers in farms, cleaning agents at home, and chemicals in working places. Finally, electricity was the best invention discovered during this time. Because of electricity, more things are being discovered and invented. Telegraphy, radio and telephone soon follow. Therefore, this was the Continue reading...