Answer Bank observation theory law inference principle fact hypothesis a proposed explanation of an observation based on scientific knowledge that must be testable and falsifiable a logical conclusion based on observations and existing knowledge a statement of repeated observations, not including an explanation of those observations an explanation for a set of observations or natural phenomena based on repeated testing a widely accepted theory or law an observation that has been repeatedly confirmed and accepted as true information obtained from the use of one or more of the five senses, the first step in scientific inquiry