The Role of Theories, Laws, Hypotheses and Models  The terms that describe examples of scientific knowledge, for example:”theory,” “law,” “hypothesis,” and “model” have very specific meanings and functions within science. Scientific Ideas Scientific Ideas are developed using evidence gathered from scientific observations. In turn, these ideas can be used to help you understand and explain what you observe in the natural world. Models, theories and laws are all types of scientific ideas. A scientific model is a simplified representation of a part of the natural world that explains what that part looks like or how it works. Models are often used to represent things that cannot be observed directly, like individual water molecules or the center of the Earth. Models can represent things that are too small, too large, happen too slowly or too quickly. Drawings, objects, mathematical equations, and computer simulations can all be models. Did you know? Albert Einstein described science this way: “The whole of science is nothing more than a refinement of everyday thinking.” A theory is a set of ideas that tie together many observations. For example, the theory that the universe is expanding is based on many observations showing that objects in space are moving farther and farther from one another. Theories are based on ideas that have been tested and shown to be true over time. A theory usually explains many hypotheses. A scientific law is a statement about how things work in nature that seems to be true all the time. Laws tell you what will happen under certain conditions but do not necessarily explain why it happened. For example, the law of universal gravitation explains how the force of gravity affects all objects in the universe. Like theories, laws are based on ideas that have been tested by observations and experimentation. Scientific Model Scientific Ideas can never be “proven”. They can only be supported by scientific observations. The more observations others gather that agree with an idea, the more support the idea gains. Theory Law If observations do not support a scientific theory, the theory must be changed. Observations should never be changed to match scientific theories. Did you know? The word inquiry comes from the Latin verb inquirere meaning “to seek”.

Hypothesis ….hmmm so are they the same? Did you know? The plural for Hypothesis is Hypotheses. A hypothesis is an idea that can be tested by an experiment. All experiments should have a hypothesis. The hypothesis might be a positive statement (“All objects fall at the same speed”) or a negative statement (“Plants will not grow in the dark”). All hypothesis should be testable. Warning!!! “When theories are proven they become laws” FALSE INFORMATION! Because scientific laws and theories serve different purposes, the common notion that when theories are proven they become laws is misguided. Theories and laws are different kinds of knowledge and play different roles in science. As such, one can never become the other. Because both laws and theories are based on evidence, which always has the potential to change with new observations and experiments, neither is absolute. Laws are no more proven than theories – both are subject to change. The difference between a "law" and a "theory" often confuses people. This happens because even among scientists there can be different usage of these terms. As used in science, it is important to realize that, in spite of the differences, these terms share some things in common. Both are based on tested hypotheses; both are supported by a large body of empirical data; both help unify a particular field; both are widely accepted by the vast majority (if not all) scientists within a discipline. Both scientific laws and scientific theories could be shown to be wrong at some time if there is data to suggest so. So What is the Difference Between a Theory and a Law??? For Example – Darwin gathered all of his evidence about animals’ traits from his observations. He made sure he had recorded his observations accurately. He then used his notes, his observations, and his knowledge of geology to develop a hypothesis about how he thought animals had gotten their difference traits. A hypothesis is a prediction based upon those observations. It predicts what is going to happen between an independent (manipulated) variable and a dependant (responding) variable. Using the evidence from his observations and what he learned from other scientists, Darwin developed at theory explaining the variation. A scientific theory is a broad explanation that is strongly supported by a body of evidence, which in this case was observations. The Role of Theories, Laws, Hypotheses and Models  The terms that describe examples of scientific knowledge, for example:”theory,” “law,” “hypothesis,” and “model” have very specific meanings and functions within science. Many hypothesis turn out to be wrong. However, even wrong hypotheses are useful because they help you rule out some ideas. Some scientists will tell you that the difference between them is that a law describes what will happen, and will predict what will happen as long as those conditions are met. A theory explains why it happens.