Scientific Terminology Spikes

It turns out to be interesting to give obscure mathematical terms to Google's Ngram service, which measures the prevalence of words in historical published works. Take haversine, a function from trigonometry that is not taught in high school today but is frequently used in navigation:


Looking at the spikes, I conjecture that during the World Wars, a lot of people were studying navigation!

On a somewhat melancholy note, look at tensor and differential equation:

I interpret the peaks here as the Kennedy Moon Race, and the push for increased science education that went with it.