When you take a good look at something, noticing facts or taking measurements, you are engaging in observation, something a little more intense than just a quick glance. When you share an observation, you communicate an insight.
The Latin verb observāre, "to attend to," is the foundation for our word observation, which requires that you pay attention. If a hospital holds you overnight for observation, they want to keep an eye on your condition. If you have a lot of funny or interesting observations on a topic, maybe you should write a book. Scouts founder Robert Baden-Powell once said, "If you make listening and observation your occupation you will gain much more than you can by talk."