sentences:  It was observed that personal intervention by the scientist allowed more accurately targeted observations and less incidental damage compared to blind sampling from the surface, and that the observation of the subject by the scientist can provide valuable and often unexpected data.There are also phenomena and organisms that are difficult or impossible to observe except by being there, and places that are difficult to access other than by going there in person.It is difficult to determine the full scope of underwater science in the past, as not all work or methodologies have been published.