Designing an Experiment and Making a Graph

How do physicists design, carry out, and analyze experiments?

View or print all handouts for this unit here.

Making a Graph in Logger Pro:
We're often going to be making graphs in a program called Logger Pro. The following video will guide you through the process of making a correct graph.

Data Section of a Lab Report:
When you present your results in a lab report, the content of your "Data" section must be very specific. The following video wil guide you through the process of making an excellent data section.

HINT: This video contains important information in blue boxes showing "text annotations." Don't ignore this information, just because the narrator isn't talking about it directly!


PhET Pendulum Experiments:
In many experiments, we're looking for the relationship between the independent variable and the dependent variable. But even for the same situation, which factor is called the independent or the dependent variable will change depending on details of the experiment. The simulation below shows a object that swings back and forth from a string - often called a pendulum. We can use this program to answer many different research questions, but we'd need to choose our independent and dependent variables closely.

HINT: To make all the measurements you can in the simulation, try turning on the tools near the bottom right of the simulation. Play with them to see what they do.

• What research questions could you answer using this simulation?

• Describe how you'd carry out an experiment to answer one of these research questions. What measurements would you make? What variables would you have to hold constant as controlled variables? How would you organize your data? How might you analyze the data you collect?

• What is the relationship between the mass of the swinging object and the time it takes for the pendulum to perform one complete cycle? Answer this research question by planning and carrying out an experiment, then analyze your results using a graph.

• Analyze a research question of your own design. Make sure to clarify the independent and dependent variable in your investigation, as well as any variables that you'll hold constant as controlled variables.