Because the competitive landscape of the web is such that the site which looks and works best gets the most traffic, developers and designers put a premium on the presentation of that content and let structural markup take a back seat.
The mystique associated with the bomb, the role that scientists played in it, and its general importance could not fail to impress even a six-year old.
There are two possible outcomes: if the result confirms the hypothesis, then you've made a measurement. If the result is contrary to the hypothesis, then you've made a discovery.