Humans are an inquisitive bunch. They want to understand why the world is the way it is. Science offers us a method to obtain objective and reliable knowledge, even though scientific knowledge will never be absolutely right and can never be irrefutably and irretrievably proven.
Knowledge can be passed on orally, but also in writing, through models, in art, etc. In the world of science, we tend to spread knowledge via publications. This way, other scientists are able to provide comments, start discussions, as well as adjust data and findings.