Scientific METHODS .pdf

Scientific theories are concepts that join well- supported and related hypotheses. In science, a theory is supported by a broad range of observations, experiments, and data. Examples: cell, homeostasis, evolution. The theory of evolution is the unifying concept of biology. Basic and Applied Scien...

Scientific theories are concepts that join well- supported and related hypotheses. In science, a theory is supported by a broad range of observations, experiments, and data. Examples: cell, homeostasis, evolution. The theory of evolution is the unifying concept of biology. Basic and Applied Science Basic science - the only goal of basic science research is to increase the knowledge base of a particular field of study. Not focused on developing product or service- knowledge for knowledge’s sake is main purpose Applied science - aims to use science to solve real-world problems, by using the knowledge base supplied by basic science Some believe it is useful **Work together to solve practical problems - after discovery of DNA **Another link is Human Genome Project Hypothesis Testing Scientific method - is the process of tangibly establishing facts through testing and experimentation. The basic process involves making an observation, forming a hypothesis, making a prediction, conducting an experiment and finally analyzing the results. Hypothesis - suggested explanation that can be tested After hypothesis, prediction can be made Must be testable to ensure it is valid Should also be falsifiable- can be disproven through experiment © McGraw Hill LLC Observation Scientists tend to be curious about nature and how the world works. Natural phenomena may be better understood by observing and studying them. Scientists use their senses to make observations. They can extend their abilities by using technology–for example, instruments such as the microscope. Hypothesis Inductive reasoning occurs when specific observations are used to develop a general explanation, idea, or hypothesis. A scientist states a hypothesis, a tentative explanation for a natural event. It is presented as a falsifiable statement. A scientist's past experiences may influence his or her hypothesis. Hypotheses should be testable. Predictions To determine how to test a hypothesis, scientists use deductive reasoning. Involves “if, then” logic. For example, a scientist might reason, if organisms are composed of cells, then examination of an organism should reveal cells. One can also imply that the scientist has made a prediction. Experiments To test their hypothesis, scientists conduct experiments. Experimental design. Experimental variable: factor tested. Responding variable: result or change. Control: not exposed to experimental variable. Predictions and Experiments Cont’d Experiments in controlled studies have two types of groups: Control group–receives no treatment. Experimental group–receives treatment. **Scientists often use a model, a representation of an actual subject. Experimental Variable (Independent Variable) Factor of the experiment being tested Response Variable (Dependent Variable) Result or change that occurs due to the experimental variable Presenting and Analyzing the Data 2 Scientific studies are usually written up as research papers and submitted for publication in scientific journals. Scientific papers are first reviewed by experts and may be rejected. After any necessary revisions, scientific studies may be accepted for publication in scientific journals. Example of the Scientific Method Experimental background: Most stomach and intestinal ulcers are caused by the bacterium Helicobacter pylori. Antibiotics are used to treat this condition. Which of two antibiotics is best for the treatment of an ulcer? In the experiment, vary only the antibiotic being tested; control group receives no treatment. The Experiment 1 HYPOTHESIS: Newly discovered antibiotic B is a better treatment for ulcers than antibiotic A, which is in current use. PREDICTION: Antibiotic B is a better treatment for ulcers than antibiotic A. Results and Conclusion Results: After two weeks, a higher percentage of those treated with antibiotic B were effectively treated. Conclusion: Based on their data, the investigators concluded that their hypothesis has been supported.