Pain in the Big Toe. Gout is a notorious cause of sudden pain in the big toe joint, along with redness and swelling (seen here). Osteoarthritis is another culprit that causes pain and swelling. If the joint is rigid, it may be hallux rigidus, a complication of arthritis where a bone spur develops.
But to see it more clearly: scientific observation is to view  the movements, and effects of those movements, or to view any  situation, and the effect of it.   Example: I saw a fish swim though the water. So based on what I  observed, I ask questions, like, how did the fish swim though the  water.
Definition of science for English Language Learners. : knowledge about or study of the natural world based on facts learned through experiments and observation. : a particular area of scientific study (such as biology, physics, or chemistry) : a particular branch of science. : a subject that is formally studied in a college, university, etc.