Scientific method

• Biology


  The study of living things
• Science


  The organised and objective study of the physical, material and living world
• Originally biology consisted of

  • Botany (study of plants)
  • Zoology (study of animals)
  • Microbiology (study of small living things)
• Areas of study in biology

  • Taxonomy (classification)
  • Anatomy (overall structure)
  • Physiology (overall function)
  • Cytology (cells)
  • Biochemistry (chemical reactions)
  • Ecology (relationships between living things and their environments)
  • Genetics (inheritance)
• Microbiology can be divided into


  • Bacteriology (bacteria)
  • Mycology (fungi)
  • Virology (viruses)
• Some areas of biological study

  • Botany (plants)
  • Zoology (animals)
  • Microbiology (small living things)
  • Biochemistry (chemical reactions)
  • Physiology (overall function)
  • Anatomy (overall structure)
  • Taxonomy (classification)
  • Cytology (cells)
  • Ecology (living things and their environment)
  • Genetics (inheritance)
  • Biotechnology (use of living things to make a product)
• The scientific method

  An organised approach to solving problems by asking questions and searching for answers
• Steps in the scientific method

  1. Observation

  2. Hypothesis

  3. Experimentation

  4. Collection and interpretation of data

  5. Conclusion

  6. Relating the conclusion to existing knowledge

  7. Reporting and publishing the results
• Observation


  The most important part of the scientific method, especially when followed by asking "Why?"
• Hypothesis


  An educated guess based on observations that (a) accounts for all the facts observed and (b) leads to the prediction of new information
• Experiment


  A test for a hypothesis
• Data


  Measurements, observations or information gathered from experiments
• Conclusion


  A summary of the results of an experiment
• Theory


  A hypothesis that has been supported by many different experiments
• Principle or law


  Arises from a theory that has been shown to be valid when fully tested over a long period of time
• Variable


  A factor that may change in an experiment
• An experiment should be repeatable so that others can follow the same procedures and get the same results</b>
• Principles of experimentation


  • Careful planning and design
  • Ensure the experiment is safe
  • Design a control experiment
  • Experiments must be fair
• Control


  A comparison for the test experiment, with only one variable (or difference) between the test and control
• Replicate


  A repeat of an experiment
• Double blind


  Both the investigator and the participant are unaware of the nature of the treatment the participant is receiving
• Placebo


  A harmless, tasteless pill given to the control group at the same time as the real drug is given to the experimental group
• Double blind experiment


  • Neither the patients nor the medical staff know who is getting the placebo and who is getting the real drug
• If the control (placebo) group does not improve, and those taking the real pill do improve


  It may be the case that the drug improves arthritis
• Control group


  Provides a comparison (or standard) against which the actual experiment can be judged
• Factors to ensure fair experiments


  • Sample size
  • Replicates
  • Random selection
  • Ability to replicate by others
• Sample size


  Normally as large as possible to produce more reliable results
• Random selection


  To prevent bias (or unfairness) by the person carrying out the experiment
• Limitations of the scientific method


  • Extent of our knowledge
  • Basis of investigation
  • Interpreting results
  • Changes in the natural world
  • Accidental discoveries
• The extent of our knowledge limits the ability to form hypotheses and design experiments
• Badly designed or improperly carried out investigations will not yield valid results
• Lack of suitable controls can lead to invalid experiments with dubious results
• Faulty interpretation of results can lead to faulty conclusions and hypotheses
• Living things are constantly changing (evolving), so hypotheses and results may only apply to a particular time
• Accidental discoveries have contributed enormously to the development of scientific thinking
• The discovery of penicillin by Alexander Fleming was an accidental discovery
• Ethics relates to whether conduct is right or wrong
• Ethical issues with the scientific method


  • Use of captive animals in experiments
  • Origin of life
  • Whether evolution took place
  • How evolution took place
  • Medical issues like contraception, abortion, assisted fertilisation
  • Freezing human sperm and embryos
  • Cloning animals
  • Genetically altered plants and animals in agriculture
  • Use of stem cells from embryos
  • Organ transplants, especially from animals to humans