A hypothesis that can be tested through experimentation. The results of experimentation lead to changes in scientific knowledge. The goal of science is to understand the natural world. To achieve this goal, scientists make certain assumptions. They assume that Nature can be understood by systematic study., And Scientific ideas are open to review as well. Strong scientific ideas stand the test of time and that Science can not give answers to all questions. Scientists think of nature as a unique system controlled by natural laws. And by discovering natural laws, scientists strive to increase their understanding of the entire natural world and the laws of nature are expressed as scientific laws by counting themselves as a scientific law is a statement that describes as happening under certain conditions in nature.