Physical / Natural science e.g. Physics, Chemistry, Biology, Geography etc. deal with matter. These sciences are made by experiments on the matter in the laboratories. Since matter is a lifeless thing. Scientific Laws made in connection with the matter always prove to be exact and definite. They can be tested anywhere, for example, we study in physics that velocity will decease when pressure is increased.
Chemistry tells us that H2O always be water and in Biology protein always consists of carbon, Hydrogen, Oxygen, and nitrogen. These laws clearly show definiteness and exactness and, therefore, do not change as they represent the natural phenomena.
The difference between economic laws and Scientific Laws is as follows:
They are exact and Definite:
Scientific laws are exact and definite and they prove true in every condition. For example, an object thrown in the space, always falls on earth (Law of gravitation). Quite contrary to that. economic laws are not exact and definite. They can change at any time because human behaviour keeps on changing.
Test to Prove:
The validity of scientific laws can easily be tested, because the laboratories present to test their validity. The economic laws are related with human being and every man has different ideas which keep on changing. Therefore, it is not possible to test their validity.
A prediction can be made about scientific laws e.g., the scientists predict lunar eclipse and solar eclipse etc. The economic laws are conditional. They prove true only true in the presence of certain conditions. That is why, they cannot be predicted.
Difference in being Conditional:
Some conditions are applied while describing scientific laws but these conditions are not so exact or definite as are applied while describing economic laws.