Using a worksheet attached to this lesson, students will investigate how the length of a pendulum string affects its motion. The related curated resource, Swinging in Style, provides opportunitites for further investigations.
3-PS2-2 Make observations and/or measurements of an object’s motion to provide evidence that a pattern can be used to predict future motion. Clarification Statement: Examples of motion with a predictable pattern could include a child swinging in a swing, a ball rolling back and forth in a bowl, and two children on a see-saw. Assessment Boundary: Assessment does not include technical terms such as period and frequency.
This resource appears to be designed to build towards this performance expectation, though the resource developer has not explicitly stated so.
Comments about Including the Performance Expectation Using the Graphing Worksheet provided at the end of the lesson, students investigate how the length of a string affects the number of times the pendulum will swing in 15 seconds. It is recommended that the equation in worksheet question #3 be deleted as it is too difficult for third grade students. To make the crosscutting concept of patterns explicit, it is recommended that the worksheet be amended to have students conduct the first 3 trials at 10, 20, and 30 cm of string, then make a prediction about future motion when the pendulum string is 40 and 50 cm. in length. The first three trials should provide sufficient observational and quantitative evidence of a pattern that can be used to predict future motion.
This resource is explicitly designed to build towards this science and engineering practice.
Comments about Including the Science and Engineering Practice In this investigation, students will make observations as they count the number times a pendulum swings in a specified time period. The data will serve as the basis for evidence to explain how the length of the pendulum affects its swing. Since it is not explicitly included in the worksheet, the teacher will need to ask students to construct an explanation based on their data.
This resource appears to be designed to build towards this disciplinary core idea, though the resource developer has not explicitly stated so.
Comments about Including the Disciplinary Core Idea Students will observe that there is a pattern in the motion of the pendulum that is supported by the data collected, and use that data to make future predictions. As the length of the pendulum increases the size of the swing, the result is a decrease in the number of swings per period.
This resource appears to be designed to build towards this crosscutting concept, though the resource developer has not explicitly stated so.
Comments about Including the Crosscutting Concept Students will observe that there is a pattern in the motion of the pendulum that is supported by the data collected. If the lesson is structured as recommended for the Performance Expectation, then students can use the data to make future predictions. Teacher facilitation as students discuss their data is key to making the patterns explicit.
Comments about Including the Crosscutting Concept While patterns is the predominant crosscutting concept here, relationship between the length of the string (cause) and the resulting motion of the pendulum (effect) can be identified and used to explain change as the students conduct their investigations.