Student Portal:

Open Inquiry: The Pendulum










This Investigation is designed to:

  • allow you to solve a problem that incorporates scientific processes and cognitive skills that have been introduced during the previous CELLs.
  • allow you to apply the Scientific Method to make a hypothesis and prediction involving the hypothesis.
  • Allow you to design and conduct your own experiment and interpret your results.
  • Allow you to determine if your prediction and hypothesis were correct.


Student Preparation for the Investigation includes gathering the following materials. 

Note: The materials are listed in your SDR. They are also listed below for your reference.

  • (1) ring stand and support rod
  • (1) protractor
  • (1) pair of scissors
  • (1) stopwatch
  • (1) meter stick
  • (5) sets of gram masses (20g, 50g, 100g, 200g)

One student from each lab group should collect the materials listed above and in the SDR.



  • Reflect on the Concepts Day presentation as you move through the Scientific Method Form.
  • Complete the Scientific Method Form in your SDR.

 Note: The Key Terms and Scientific Method, as they appear in your SDR, are listed below for your reference.

Key Terms:

  • Length (L): The length of the pendulum is the distance from the center of the gram mass to the point of support.
  • Period (T): The period of the pendulum is the time required for the gram mass to leave one extreme position, swing to the other extreme, and then return.
  • Amplitude (A): The amplitude of the pendulum is the angle between the string at the vertical position (mass hanging straight down) and the string at either extreme of the swing.
  • Mass (M): The mass of the pendulum is the mass of the attached gram mass.

The Scientific Method:

  1. Observation: Make general observations about the system you are studying. For example, what are its parts, why is it of interest, what are potential variables.
  2. Question: Based on the variable assigned to your group by your teacher, ask a question(s) about how this variable is related to other variables and what might happen if you begin to make changes in the variables.
  3. Hypothesis: Based on the question(s) you have posed, form and state a hypothesis that involves your assigned variable.
  4. Prediction: Make a prediction, based on your hypothesis, which can be tested in an experiment.
  5. Test: Design an experiment to test your prediction. Prepare a data table so that you can accurately record your results in the lab. Decide how many times you will repeat measurements to increase accuracy, what range of variables you will use, etc. Identify your dependent and independent variables. List the equipment you will use. Identify potential sources of error and attempt to control them.
  6. Data: Accurately record data in your data table. Identify expected and unexpected sources of error and steps you took to eliminate or control them. Plot your data. Remember, the independent variable is typically plotted on the x-axis while the dependent variable is plotted on the y-axis.
  7. Conclusions: Does your data indicate whether your prediction was true or false? What do the results tell you about your hypothesis? If your data was not accurate or you encountered unsolved problems, how might you approach the experiment differently if you were given another chance to do so?


Be sure to clean up your lab bench after completing this Open Inquiry.