The laws of science, scientific laws, or scientific principles are statements that describe or predict a range of phenomena as they appear in nature. The term "law" has diverse usage in many cases: approximate, accurate, broad or narrow theories, in all natural scientific disciplines (physics, chemistry, biology, geology, astronomy etc.). Scientific laws summarize and explain a large collection of facts determined by experiment, and are tested based on their ability to predict the results of future experiments. They are developed either from facts or through mathematics, and are strongly supported by empirical evidence. It is generally understood that they reflect causal relationships fundamental to reality, and are discovered rather than invented.