1.1.2 Scientific Method

The Scientific Method The Scientific Method involves the following steps: Making observations Formulating a hypothesis Designing a controlled experiment Collecting and interpreting data Forming a conclusion Comparing the conclusion with existing knowledge Reporting and publishing the results Developing theories and principles

Scientific Method 1.1 THE SCIENTIFIC METHOD (2 class periods) Biologists seek solutions to problems that relate to the living world and employ processes of science that lead to the discovery of new knowledge. The process of science can be termed the scientific method. Even though the scientific method is quiet variable, it is possible to point out certain steps that characterise the scientific method: Making observations Formulating hypotheses to explain the observations Testing the validity of the hypotheses by designing a controlled experiment Collecting and interpreting the data from the experiment Coming to a conclusion Placement of conclusions in the context of existing knowledge Reporting and publishing results Which may lead to the formation of theory and scientific principle The observations ,hypotheses and experiments are documented in accessible sources where all can examine them. These results are expected to be repeatable, that is, to be obtained by anyone following the same procedure. It is the aim of enquiry to formulate theories and principles to explain the existence, development and functions of the natural world. The scientific method may be used in areas that raise ethical issues. In recent years such contentious issues have been mainly related to the origin of life, human reproduction, medicine and developments in biotechnology

The Edward Jenner Story

e.g. Edward Jenner’s investigation The Scientific method e.g. Edward Jenner’s investigation Jenner noticed that people who caught Cowpox (a minor disease) did not seem to get Smallpox (a fatal disease). Jenner hypothesised that if someone got cowpox and recovered then they would not get smallpox. The Scientist makes an Observation A hypothesis is formed. (A hypothesis is an educated guess based on the initial observation).

An experiment is designed to test the hypothesis. 4. Interpretation of results. 5. Conclusion Jenner injected a boy with cowpox and later injected him with smallpox. Jenner tested the boy for smallpox and found that he did not have it. Jenner concluded that a person who once had cowpox would not get smallpox.

Based on the results of an experiment a hypothesis can be supported, rejected or changed and retested. Details of the experiment and the results can be published in a Journal to inform the scientific community and allow further research. If a hypothesis is continually supported by many experiments it becomes known as a theory. When a theory has been shown to be correct under all conditions then it becomes known as a Law or Principle.

Observation You observe something using your senses or machines which are basically extensions of those senses.

Question You ask a question about what you observed. Form a question about a specific event or reaction State it as a problem or question. E.g. How does human activity affect global warming? Why are honeybee populations suddenly declining in North America? What enables birds to migrate such long distances? How do black holes form?

Design an Experiment Devise a way to test whether your hypothesis is correct or not. Create a controlled experiment. A controlled experiment MUST have 2 groups. The outcome must be measurable. Record and analyze data.

Collect & Analyze Data You do the experiment(s) using the method you came up with and record the results. You repeat the experiment to confirm your results.

Two Types of Data QUANTITATIVE: numerical data, deals with specific quantities, usually in the form of a graph or chart QUALITATIVE: descriptive data, describes how something looks, smells, sounds, or feels; deals with qualities

Learning check What is the next step? The Conclusion

Draw Conclusions Determine from the data collected if the hypothesis was correct or incorrect Try to explain your results.

Compare You compare your conclusion with existing knowledge.

Finally You Report and Publish your results. You Develop a theory or principle.

Progression of Ideas in Science Hypothesis- a possible explanation to a question based on information the scientist has already gathered If experiments show a hypothesis to be correct, other scientists may accept it as support for a scientific theory. Eg: Plants obtain their energy from the sun.

Scientific Theory - a general statement of why things work based on hypotheses that have been tested many times Scientific Law - a statement of what happens in a certain event based on verified observations & experiments

Progression of Ideas in Science Which one is most likely to be wrong- hypothesis, theory, or law? 1. 2. 3. Hypothesis Theory Law

What are the main steps in the Scientific Method? Observation Hypothesis Experiment Result Conclusion

Steps in the scientific method Observation Question Hypothesis Test/Experiment Results Conclusions

Limitations of the Scientific Method

Limitations of the Scientific Method Is limited by the extent of our basic knowledge is limited to what can be observed with the five senses tells us “how” a process works, not “why” e.g., does not really explain why the Universe exists may be affected by the emotional involvement of investigator may be affected by time pressure for results

Limitations of the Scientific Method limitations of our measurement instruments ethical and legal responsibilities religious beliefs we can never be sure all untested variables are controlled scientists sometimes make mistakes

Song on Scientific Method

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Websites of Interest http://www.sciencebuddies.org/science-fair-projects/project_scientific_method.shtml http://www.biology4kids.com/files/studies_scimethod.html http://science.howstuffworks.com/scientific-method.htm

Expt to demo the scientific method