Understanding the Scientific Method in Medical Science

1. Science is process in which experiments are used to answer questions.  This process is called the scientific methodand involves several steps:

2. 1. Identify the Problem or form a question 2. Observation and research 3. Hypothesis- predicted guess • Procedures and conduct an experiment 5. Gather & analyze data 6. Report results or Conclusion

3. The scientific method

4. Medical Science

5. Steps of the scientific method: 1. Define the problem - This is usually a question. Example: "Does acid rain affect the development of salamanders?" 2. Observation & research – make observations. Research library information on: • Salamanders, acid rain, acids and bases, etc. • Sources could include: books, journals, internet articles, etc.

6. 3. Form a Hypothesis (educated guess or tentative explanation) • Logical statement that potentially explains an event, or answers a question. • The hypothesis is a statement that can be tested. • Example: "Salamanders that develop under acid rain conditions show a greater number of developmental abnormalities than salamanders that develop in unpolluted waters."

7. 4. Procedures & Conducting the Experiment 1. make a set of procedures 2. make a list of materials 3. Make sure the experiment is reproducible

8. Parts of an Experiment • Controlled experiment - all the conditions are alike except the condition being tested. • VARIABLE - the one condition that is tested. • • The EXPERIMENTAL GROUP is exposed to the variable. • The Control or CONTROL GROUP is raised under normal conditions, without the variable. It is a standard used for comparison - Only one variable may be tested at a time.

9. Variables • Variables that depend on each other are called dependent variables. • So if the variable "a" changes and causes a change in variable "b" then b is said to be dependent on "a". (graphed on y-axis)

10. 5. Variables Independent variables are those which do not depend on each other, such as density and area of a liquid. (Graphed on x-axis)

11. Dependent Responding on Y axis Manipulated Independent on X axis DRY MIX

12. 5. Gather & analyze data • Measurements are important. • The scientist may use drawings, tables, graphs, diagrams, photographs, written observations, or sound recordings.

13. 6. Drawing Conclusions • summary that accepts or rejects the hypothesis based on facts or data • Statistics may be used to evaluate data.

14. A conclusion will often lead to another question, which will lead another experiment, which can lead to another conclusion, and on and on.

15. Development of Theories and Laws Outcomes Over the Long-Term • Theory (Model) * A set of tested hypotheses that give an overall explanation of some natural phenomenon. * widely accepted, plausible generalization about fundamental scientific concepts that explain why things happen • Natural Law - A uniform or constant fact of nature that describes what happens in nature. - The same observation applies to many different systems - Example - Law of gravity

16. Theory vs. Law • A theory or law in the world of science is a hypothesis, or many hypotheses, which have undergone rigorous tests and have never been disproved. • There is no set number of tests or a set length of time in which a hypothesis can become a theory or a law.

17. Theory vs. Law • A hypothesis becomes a theory or law when it is the general consensus of the scientific community that it should be so. • Theories and laws are not as easily discarded as hypotheses.

18. Limitations of Science - Restricted to those things that can be logically tested and falsified. - More than one hypothesis can predict the same outcome of a test. - Results can be interpreted in different ways, leading to different conclusions. - Hypotheses constantly being reevaluated and modified as more results and information are gained.