There are two paramount differences between art and science. The first is that art is subjective while science is objective. The second is that art expresses knowledge, most often in the form of subjective representation, while science is the system of acquiring knowledge. Art and science are therefore in fundamental character very dissimilar.
Science is concerned with general truths about the operation of general laws pertaining to the physical (and quantum) world and relies on methods of study and data accumulation based on observation and experimentation. The primary method is called the scientific method, which not only allows for methodical knowledge collection but also allows for confirmation of knowledge as other scientists replicate and corroborate observations, experiments, results, and conclusions.
Art, which transcends historical and cultural features and therefore has trans-historical and trans-cultural characteristics, is concerned with aesthetics and is said to have a relatively "stable aesthetic core" united with perceptual properties. This definition roughly covers varying traditionalist, conventionalist, contemporary, and functional definitions of art. Aesthetic is a heightened sensitivity to "beauty" and "good taste."