Googles.
Ngram Viewer is a search tool that trainees can utilize to explore using words and names in books published between 1800 and 2019. The Ngram Viewer shows users a chart illustrating the first look of a word or name in literature and the frequency with which that word or name appears in literature because 1800. The graph is based on the books and periodicals that are indexed in Google Books.

Ngram Viewer is a search tool that trainees can use to explore the usage of words and names in books released in between 1800 and 2019. The Ngram Viewer shows users a graph illustrating the very first look of a word or name in literature and the frequency with which that word or name appears in literature considering that 1800. The Ngram Viewer will let you compare the use of multiple words or names in one chart.

The Ngram Viewer will let you compare using several words or names in one chart. The example that I give up this video is to compare using the terms “National Parks,” “National Forests,” and “National Forest Service.” By looking at the Ngram Viewer for those terms I can see that they start to appear more regularly around 1890, have a lull in the 1940s and 1950s, and then appear more regularly once again in the 1960s..
Ngram Viewer is based upon books indexed in Google Books. That is why listed below every chart created by Ngram Viewer you will discover a list of books about each of your search terms. Those books are arranged by date..
A third element of Ngram Viewer to keep in mind is that it works with several languages consisting of English, French, Chinese, German, Italian, Russian, Hebrew, and Spanish..

By the way, the book that I pointed out in the video is That Wild Country by Mark Kenyon..

Applications for Education.
As I mentioned in the video above, the Ngram Viewer can offer an excellent method to start a research activity for students. Have them get in a few words then examine the chart to determine peaks and valleys in the frequency of the words use. Ask them to attempt to identify what would have triggered those words to be utilized more or less regularly at different durations in history.