It involves stating some output from theory in specific and finding contrary cases among experiments or observations. The methodology proposed by Popper is commonly known as the hypothetico-deductive method . Popper's version of scientific method first begins with postulation of a hypothesis . A hypothesis is an educated guess or a theory that explains some phenomenon. A prediction is a forecast or extrapolation from the current state of the system of interest.
Predictions are most useful if they can go beyond simple forecast.
An experiment is a controlled investigation designed to evaluate the outcomes of causal manipulations on some system of interest. To get a better understanding of the hypothetico-deductive method , we can examine the following geographic phenomena. In the brackish tidal marshes of the Pacific Coast of British Columbia and Washington, we find that the plants in these communities spatially arrange themselves in zones that are defined by elevation. Near the shoreline plant communities are dominated primarily by a single species known as Scirpus americanus . At higher elevations on the tidal marsh Scirpus americanus disappears and a species called Carex lyngbyei becomes widespread.