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.
Top 10 facts about the world. Naturalistic observation is a form of research which is conducted by observing organisms in their natural environment. The observer takes meticulous notes and may also make recordings, and the period of observation can last for months or even years.