Scientific method
The Scientific Method
Chapter 1: Overview of Biology
Biology: the study of living organisms, including areas such as ecology, physiology, and anatomy.
The Scientific Method
A logical, step-by-step approach to solving problems through experimentation.
Steps in the Scientific Method:
Observation: Gathering information about the natural world or noticing an event.
Hypothesis: An educated guess based on observations; a proposed explanation or untested idea.
Experimentation: A procedure undertaken to test a hypothesis.
Collection and Interpretation of Data: Data includes any measurements, observations, or information gathered from experiments.
Conclusion: Interpreting data to prove or disprove the hypothesis.
Relating Conclusion to Hypothesis.
Reporting and Publishing Results: Scientists publish results in scientific journals for peer review, allowing others to evaluate and repeat the experiment.
Edward Jenner - Father of Immunology
Observation: Smallpox was rare among those who had been exposed to cowpox.
Hypothesis: Exposure to cowpox provides immunity to smallpox.
Investigation: Jenner injected an 8-year-old boy with cowpox pus, and after recovery, with smallpox pus; the boy did not develop smallpox.
Conclusion: Infection with cowpox prevents smallpox infection.
Hypothesis Supported: His findings supported the hypothesis.
Theory vs. Principle
Theory: A hypothesis that has been proven through repeated experiments (e.g., Theory of Evolution).
Principle or Law: Developed from a theory that remains valid over time (e.g., Principle of Gravity, Principle of Friction).
Principles of Experimentation
Careful Planning and Design: Only one variable should be changed at a time (independent variable), with remaining factors controlled (controlled variables).
Control: A standard for comparison.
Safety Considerations: Experiments must be safe.
Fairness: Ensuring fair experiments.
Sample Size and Selection
Larger sample sizes reduce the risk of results being due to individual differences.
Random Selection: Participants chosen by chance eliminates bias.
Replicates: Repeating experiments to validate results.
Double-Blind Testing: Neither the tester nor the participant knows who is receiving the placebo, eliminating bias.
Limitations of the Scientific Method
Extent of Knowledge: Hypotheses may be wrong without sufficient knowledge.
Basis of Investigation: Poor instrumentation can hinder discovery (e.g., the cell).
Interpretation of Results: Limited knowledge affects result interpretation.
Changes in Natural World: Evolution and environmental adaptations affect organisms.
Accidental Discoveries: Discoveries, like antibiotics by Alexander Fleming, occur by chance.
Possible Sources of Errors in Experiments
Too small sample size.
Changing multiple variables.
Non-random sample selection.
Scientific Method Questions
What is a hypothesis?
What might a hypothesis develop into?
Why is a control important in an experiment?
Explain the purpose of a control in a scientific experiment.
Explain each of the following in relation to the scientific method: hypothesis, control, data, replicate, theory.
As a result of her observations, a scientist may formulate a _____, and then devise a series of _____ to analyze the resulting _____.
Why is a control especially important in biological investigations?
Suggest a suitable control when determining the effect of a herbicide on weed growth.
What are replicates in scientific research?
Where may a scientist publish her results?
Why is a control used when carrying out an experiment?
Why is it a good idea to repeat experiments?
Why are controls important in experiments?
In relation to the scientific method, explain the terms: (i) Experiment and (ii) Theory.
Discuss the effect of a certain mineral on the growth of wheat based on scientific methods and lab procedures.