Final answer:
Scientists distinguish between investigations and experiments because not all scientific inquiries involve the controlled testing of hypotheses that defines an experiment. An investigation can include various methods of exploration, whereas experiments are a structured component of the scientific method aimed at empirical evidence gathering.
Step-by-step explanation:
Scientists say that every investigation is not an experiment for several key reasons. While experiments allow scientists to probe cause and effect and to make claims supported by empirical evidence, investigations encompass a broader range of scientific inquiries. An investigation can include gathering preliminary data, observing natural phenomena, or conducting surveys, which might not have the controlled variables necessary for an experiment.
An experiment involves a more structured approach where a hypothesis is tested under controlled conditions to see if it holds true. Experiments are a critical component of the scientific method, providing evidence through observations made during the process. However, science is not limited to experiments alone; it includes a vast array of research methods aimed at exploring, explaining, and understanding the natural world. Due to the complexity of the natural universe and the limitations of human understanding, not all questions can be addressed with a simple experiment. Furthermore, while designing an experiment, scientists often rely on existing knowledge, which can sometimes lead to overlooking unexpected findings that do not fit established theories.
Moreover, scientific reasoning is multifaceted, and the scientific method is not always followed in a linear fashion. Scientists need to adapt their methods, draw inferences, and make generalizations as new evidence or questions emerge from their research. This non-linearity and the need for flexibility in the approach show that investigations are not limited to experiments and that the process of science is much more dynamic.
In conclusion, the nature of scientific inquiry is such that it involves a series of investigations, of which only some take the form of experiments. An investigation is broader and multifaceted, while an experiment is a more specific type of investigation designed to test hypotheses in a controlled manner.