Since this seems to be the absolute biggest misconception on these forums, I will explain the difference between the three above terms when it comes to science. [b]Facts[/b]  Facts are statements that we know to be true through direct observation. In everyday usage, facts are a highly valued form of knowledge because we can be so confident in them. Scientific thinking, however, recognizes that, though facts are important, we can only be completely confident about relatively [b][u]simple statements[/u][/b]. For example, it may be a fact that there are three trees in your backyard. However, our knowledge of how all trees are related to one another is not a fact; it is a complex body of knowledge based on many different lines of evidence and reasoning that may change as new evidence is discovered and as old evidence is interpreted in new ways.  [b]Laws[/b] A law is a description of an observed phenomenon. It [b]doesn't explain why it happens or what causes it.[/b] For example: the law of gravity- two bodies in the universe attract each other with a force that is directly proportional to the product of their masses and inversely proportional to the square of the distance between them. This describes an observable phenomenon, but doesn't tell us why, or how it happens. For the example above we would need to look to the Theory of Gravity to know how or why that law is a law. One of the biggest misconceptions is that scientific theories become laws, which isn't true. Law doesn't mean that it can't be changed through scientific research in the future. The use of the word "law" by laymen and scientists differ. When most people talk about a law, they mean something that is absolute. A scientific law is much more flexible. It can have exceptions, be proven wrong or evolve over time, according to the [url=http://undsci.berkeley.edu/teaching/misconceptions.php#a2] University of California. [/url] [b]Scientific theory[/b] In everyday language, the word theory is often used to mean a hunch with little evidential support. Scientific theories, on the other hand, are broad explanations for a wide range of phenomena. They are [u]concise (generally don't have a long list of exceptions and special rules), coherent, systematic, and can be used to make predictions about many different sorts of situations.[/u] A theory is most acceptable to the scientific community when it is strongly supported by many different lines of evidence — but even theories may be modified or overturned if warranted by new evidence and perspectives. [b]Theories tell us how and why.[/b] So as you can see, to equate theory to merely a guess is not only fool hearted, its wrong. Laws are direct observations, theories are the how and the why, and while they are both supported by strong empirical evidence, they can still change, and be updated, as new information is found. But, they get stronger and stronger as they continually have more and more evidence found to support them. Think a little more next time you claim a scientific theory is " just a theory" and then dismiss it based on some misrepresented information and logical fallacy. Example: evolution.