They were going to study the lake?!? That sounded strange, but interesting nonetheless. Maybe it was going to be like Muggle geography. Or not. 'Since Hogwarts was founded with the purpose of educating generations of students, I'm guessing the lake was used to study merepeople and other aquatic creatures in their own habitat, just like the edge of the Forbidden Forest is a good place to study unicorns or thestrals.' the Gryffindor ventured, after raising her hand.