This resource is explicitly designed to build towards this science and engineering practice.
Comments about Including the Science and Engineering Practice
As described in the tips for the Performance Expectation, students will make observations and take measurements to produce data that explains a force has strength and direction. It should be noted that the different starting points at which the pencil starts are identified as trials. As trials are defined as a set of repeated measurements (ScienceSaurus, 2005), it is suggested that they be identified as “Push Points” instead. Teachers may also want to have the students conduct replicable trials from each push point to increase the reliability of their data. As the averaging of data points is not addressed in the Common Core Standards for Mathematics until the later grades, the students could take the median of each data set instead.
The technique to push the balls is not described in this lesson. While pushing the pencil like a pool cue works, laying the pencil horizontally on the push point line and flicking it to hit both balls simultaneously is also effective. The teacher may want to engage students in soliciting ideas and exploring the best method for pushing the balls. It is also recommended that the technique for pushing the ball be practiced before experimentation to enable better control of this variable. Lastly, a discussion of the term variables and how they might affect the outcome of their investigations is suggested.