What is science? Science consists of two things: a body of knowledge and the process by which that knowledge is produced. This second component of science provides us with a way of thinking and knowing about the world. Commonly, we only see the "body of knowledge" component of science. We are presented with scientific concepts in statement form - Earth is round, electrons are negatively charged, our genetic code is contained in our DNA, the universe is 13.7 billion years old - with little background about the process that led to that knowledge and why we can trust it. But there are a number of things that distinguish the scientific process and give us confidence in the knowledge produced through it. So then, what is the scientific process? The scientific process is a way of building knowledge and making predictions about the world in such a way that they are testable. The question of whether Earth is flat or round could be put to the test, it could be studied through multiple lines of research, and the evidence evaluated to determine whether it supported a round or flat planet. Different scientific disciplines typically use different methods and approaches to investigate the natural world, but testing lies at the core of scientific inquiry for all scientists. As scientists analyze and interpret their data (see our Data Analysis and Interpretation module), they generate hypotheses, theories, or laws (see our Theories, Hypotheses, and Laws module), which help explain their results and place them in context of the larger body of scientific knowledge. These different kinds of explanations are tested by scientists through additional experiments, observations, modeling, and theoretical studies. Thus, the body of scientific knowledge builds on previous ideas and is constantly growing. It is deliberately shared with colleagues through the process of peer review (see our Peer Review module), where scientists comment on each other's work, and then through publication in the scientific literature (see our Utilizing the Scientific Literature module), where it can be evaluated and integrated into the body of scientific knowledge by the larger community. And this is not the end: One of the hallmarks of scientific knowledge is that it is subject to change, as new data are collected and reinterpretations of existing data are made. Major theories, which are supported by multiple lines of evidence, are rarely completely changed, but new data and tested explanations add nuance and detail.