Types of Scientific Studies

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					Types of Scientific
There are 3 main types of
scientific studies
  1) Observational studies
  2) Controlled experiments
  3) Correlation studies
Steps in Scientific Studies

  All 3 types of studies include the following
       Making an observation
       Developing a question or problem
       Stating an Hypothesis
       Designing an experiment or method to obtain data
       Collecting and recording data
       Analyzing data
       Communicating results
Controlled Experiments

  A type of scientific study where one variable
   (the independent variable) is purposefully and
   steadily changed to determine the effect on a
   second variable (the dependent variable). All
   other variables are kept constant.

  As a result, cause (the independent variable)
   and effect (dependent variable) are closely
Examples of Controlled
   Independent Variable     Dependent Variable
1) Increasing the         1) Incidence of tooth
   amount of candy           decay
2) Increasing the         2) Amount of rust on
   amount of salt on         metal parts
   winter roads
3) Increasing the         3) Student grades
   number of hours
   spent studying
Observational Studies

  Used to gather scientific information by
   observing natural phenomena without
   interfering with the normal order of the

  These studies do not use independent
   and dependent variables
Examples of Observational
  Water temperature and population of
   perch in a lake
  Combining hydrochloric acid and
   magnesium metal
  Combining copper II sulphate and
   calcium carbonate
Correlational Studies

  A type of scientific study where scientists
   determine if one variable affects a
   second variable without directly changing
   the variables – instead the variables are
   permitted to change naturally
Examples of Correlational
  1) The effect of drinking alcohol on a
   pregnant mother
  2) How the amount of time listening to
   loud music affects hearing loss
  3) The relationship between obesity and
   heart disease