The State Library has a rare online database of Iowa inventors and inventions from 1843-2009. It is searchable by inventor's name, title of the invention, the inventor's residence (town or county), date the patent was granted, and patent number. Did you know there were 1,738 patent from 1900-1902 and 4,450 patents from 2000-2002.
If you look at the 1900-1902 patents and then used the timeline feature in netTrekker, http://school.nettrekker.com, you could help students put those inventions in context with what happening in the world. 1900-1902 was the time of Gilded Age and Early Modernism, the Boxer Rebellion, Boer War, allied intervention, Casey Jones, the control of Yellow Fever, discovery of radioactive half-life, etc.