How has the American agriculture changed during this last century?

What is a 20th century American invention that has changed throughout time (ie phones)?

• I need to know any easy, flexible American invention from the 1900s to write about for my report, for example: Telephones evolved over time up to now, being cell phones. Any invention is fine excluding telephones because it's too cliched. Thanks!

• Answer:

  I think one of the most fascinating American Invention of the 20th Century is the Powered Aircraft. While theories about the powered flight date back to the ancient greeks (a greek philosopher suggested what amounts to a ram jet over 2000 years ago, if I am not mistaken.) it was not accomplished until the early 20th century, By Wilbur and Orvil Wright. Some of the others that have been listed, by the way, are not American Inventions, and/or not from the 20th Century. Do your research. (The first automobile, some would say, was made by Mr. Benz in Germany in 1886, for example. Telegraph, Pony Express, Calculators (The abacus), etc. all were around long before the beginning of the 20th Century. The US Mail has been around since the founding of the country. Timepieces have been around since before any westerner had even made it to America.) Powered Flight should be easy to research. It is a wonderful and rich subject including interesting characters such as Chuck Yeager, and Charles Lindburgh. Good luck with your report. P.S. A fun site for basic research would be http://www.howstuffworks.com