Is a description of an observed phenomenon that holds true every time it is tested under a given set of conditions

An observed phenomenon description is given as scientific Law which is always true when tested in a given set of conditions.

Explanation:

A scientific law also natural law and it is described as observation of scientific events occurring naturally that can be explained using mathematical equation or other scientific explanations. Scientific laws do not explain the cause and effects; only the observation.

A phenomenon that qualifies as a scientific law must have been proven by experiments and produce similar results if simulated elsewhere by someone else. These laws can change when there is knowledge of new data or information disproving the law.

answer; seasons change because earth tilts on its axis; and the angle of the tilt causes the northern and southern hemisphere to trade places throughout the year;