By Cindy Workosky
Posted on 2019-07-17
Traditional physics education can leave many students confused, bored, or without the conceptual understanding of the equations they are required to memorize. I prefer an approach that allows students to use evidence to express, clarify, and justify their ideas so they can form their own equations based on their conceptual understandings. It is much more meaningful and helps them understand how the equation really connects to the concept it models.
It is important that students discover relationships among variables on their own, before they can create a mathematical model of the concept they are studying. Students can use the data they collect in a lab or activity to justify to their teacher and peers why they placed variables in their respective places within an equation—something the 5E Instructional Model supports. The 5E Model leads to greater understanding of science concepts, and it lends itself very well to NGSS implementation. I use the 5E Model as a template for equation discovery in the physics classroom. To show how this can be done in the classroom, I’ll explain how my students engage in each step of the 5E process in an equation discovery station lab for torque—a force that causes an object to rotate.
I begin by engaging students in an activity that catches their attention. To introduce torque, I ask the tallest and shortest students to help me with a demonstration. I ask the entire class to move to the classroom door. The biggest student pushes to open the door at the hinge while the smaller student tries to close it by pushing with a pointer finger by the door handle.
When the door easily closes, I ask students to share with the person standing next to them (while I listen in) their initial ideas as to why the door closed. What was different between Student A’s and B’s push? This exchange is very informal, as it is intended to simply open their minds to the new concept. For safety purposes, I sometimes model the demonstration first, but I always give students the opportunity to try it afterward.
I then give students the chance to explore the topic on their own, with my guidance as needed, by engaging them in conceptual station lab activities. These activities help them determine the values that concepts are directly or inversely proportional to. I set up different activities at each station with a whiteboard or large piece of paper and give each group a different colored marker. My students perform a unique experiment at each station, write what they did on the whiteboard, and record an observation. They cycle from station to station, performing experiments and developing their understanding of the concept.
For a torque lab, I set up stations that include a balancing meter stick, students “fishing” for hooked masses with a meter stick with strings to hook the mass at different points, a PhET Interactive Simulation to demonstrate rotational equilibrium, and a loop of string tied around the pages of a textbook that students attempt to open. All these stations allow students to perform experiments that test the relationship between torque (T) and the variables it depends on: distance from the axis of rotation (r) and the applied force (F). As they complete each station, they write what they did to determine if T is directly or inversely related to r and/or F and what result led them to that conclusion. One of the best things about these activities is their simplicity; you don’t need expensive equipment for your students to be able to do them.
When students have finished the activities, I ask them to bring their whiteboards to the front of the room and read their experiments and results aloud to the class. Student data and thoughts drive the conversation about what the torque concept is directly and inversely proportional to.
I give students a worksheet that lets them organize their thoughts, and when they have completed it, they ask me to “check it.” It’s not important if their ideas are correct at this point, as long as they have logical justification for their thoughts. When students have finished discussing their results with their original groups, they form new groups with at least one person from each of the original groups. My students discuss their final results with their new groups using specific data from the lab, come to consensus on an equation, and justify their thoughts with evidence from the investigations they completed.
After the equation has been formulated, I work with students to extend their knowledge. They typically are proud of the equation they created for themselves, and they understand how the equation actually connects to the real-world concept. I then give them real-world scenarios, and students begin working on practice problems. Calculations and practice problems have their place in the physics classroom, but now that students truly understand the concepts, calculations and practice problems are much more meaningful.
Finally, I evaluate student understanding, and the students evaluate their understanding themselves. I evaluate my students using an open-ended assessment that matches the learning style. Sometimes I use a student-designed Problem-Based Learning lab in which they create their own procedures to model and test a real-world problem. I use the ideas students communicate through their lab report to assess their understanding of the concepts.
Learning physics this way helps students build conceptual understanding, rather than simply learning to plug numbers into an equation. They see it as a mathematical model for a real-world concept. Science classes taught in this way are true to how science is conducted in the real world.
Typically, as students progress through science courses in school, the discovery process is replaced by the “prove this is right” process. But when scientists set out to explain something they don’t understand, they don’t know the results, so why should the way our students develop their understanding of physics be any different?
Matt Holsten is a physics and physical science teacher at Hightstown High School in East Windsor, New Jersey. He graduated from The College of New Jersey in 2016 and has been named one of New Jersey’s Top 30 Teachers Under 30 by the New Jersey Education Association Holsten plans to pursue a master’s degree and eventually a PhD in physics education. He is the proud “fur father” of a two-year-old adopted Chocolate Lab who keeps him very busy.
Note: This article is featured in the July issue of Next Gen Navigator, a monthly e-newsletter from NSTA delivering information, insights, resources, and professional learning opportunities for science educators by science educators on the Next Generation Science Standards and three-dimensional instruction. Click here to sign up to receive the Navigator every month.
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