In simple words, science establishes relationship of cause and effect whereas art is the application of knowledge comprising of some accepted theories and rules.
Accounting is an art of recording financial transaction in a set of book; classifying in desired categories and summarizing the information for presentation in a suitable manner to the concerned persons for their benefit.
Accounting is also science in the sense that it comprises of rules, principles, concepts, conventions and standards. All these form body of knowledge which has recognitions all over the world. The term GAAP denotes generally accepted accounting principles. At present we have International Accounting Standards Committee also.