OHHS Scientific Investigation Design

  1. Ask a QUESTION

    Include both the manipulated and responding variable. What is the effect of the "manipulated variable" on the "responding" (dependent) variable?

  2. Make a PREDICTION (Hypothesis)

    Provide a cause-effect reason for the responding variable to behave as predicted. If the "manipulated variable" increases/decreases, the "responding" variable will increase/decrease, because...

  3. Design an EXPERIMENT
    1. Materials
    2. Detailed Procedure
      • One manipulated variable (independent) - state at what interval or how the manipulated variable will be changed.
      • One responding variable (dependent) - state at what intervals or when the responding variable will be measured.
      • Identify at least two controlled variables (kept the same).
      • Identify an experimental control to serve as a basis of comparison.
      • Include repeated trials. The procedure should be carried out more than just once.
      • Account for issues affecting validity, for example cleaning equipment between trials.
      • Be specific enough that someone else who reads your procedure and repeated your investigation would likely get the same results.
  4. Record DATA

    Use a data table to record results. Describe the trend of the data. As appropriate, determine the mean, median or mode. Use a line graph (continuous variables), bar chart (discrete variables), pie chart or diagram to help interpret your results.

  5. Draw a CONCLUSION
    1. Answer the question or respond to the hypothesis. Support your conclusion with data. Include high and low data points. Explain how this data supports the conclusion.
    2. Always quote data accurately.
    3. Evaluate your work (quality control).
    4. What new questions might you ask?