Exploring the Relationship Between Potential & Kinetic Energy

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SWBAT use evidence to explain how movement changes potential and kinetic energy while total energy remains constant.

Big Idea

How can I maximize kinetic energy at the skate park?

The Need for the Lesson

Middle school students often have misconceptions about motion energy. One common misconception is that objects with less mass will move faster than objects with more mass. Another common misconception is that objects that are dropped do not have motion energy because gravity is simply pulling the object down.

The PhET Simulations are ideal for student exploration. This lesson has guided questions to encourage exploration to counter student misconceptions. Students will see that the mass of the skateboarder increases his total energy. The simulation also provides graphics that show kinetic energy is the energy of motion when objects fall. 

The PhET Simulations are designed specifically for student inquiry. Students can change variables in their explorations creating models that can be used to represent systems and their interactions - in this case how energy flows withing a system.

Additionally students explore the DCI (Disciplinary Core Idea) that a system of objects may also contain stored (potential) energy, depending on their relative positions.

Simulations can be a rich source for student inquiry.

Investigation Preparation & Summary

5 minutes

Students will use the PhET simulation - Energy Skate Park - as a model to explore the relationship of kinetic energy to the mass and speed of the skateboarder by changing variables. (MS-PS3-1 - Construct and interpret graphical displays of data to describe the relationships of kinetic energy to the mass of an object and to the speed of an object.) The students will refer to the graphs in the simulation to describe how distance changes the amounts of potential energy stored in a system. (MS-PS3-2 - Develop a model to describe that when the arrangement of objects interacting at a distance changes, different amounts of potential energy are stored in the system.) The simulation include options to view graphs supporting the CCSS ELA standard integrating visuals to clarify understanding and provide evidence to support student claims (SL.8.5 Integrate multimedia and visual displays into presentations to clarify information, strengthen claims and evidence, and add interest.)

Student engagement is supported as students use the Energy Skate Park simulation as a model to explain the concepts of potential and kinetic energy. Students are also developing perseverance as they extract evidence through inquiry to support their understanding of energy transfer. By changing variables to deepen their understanding, students are developing mastery as they use the simulation as an iterative process. (SP2 - Using Models)

Conducting investigations is inherent in all the PhET simulations as they allow for the change of variables that allow students to make changes in their investigation that lead to the discovery of answers to specific questions. Students in this simulation are changing variables in the simulation to understand the relationship between potential and kinetic energy. (SP3 - Planning and Conducting Investigations)

Throughout their investigations students are asked to collect observations and use the information collected to make conclusions building upon their experiences to develop habits and skills leading towards independent explorations. The lesson asks students to collection observations in a table and use that information to state conclusions about their investigation. (SP8 - Collecting and Communicating Information)

At the end of the lesson, students will experiment with pullback toy cars; comparing potential and kinetic energy using toys.

A complete material list can be found in the resource section.

Students in Action

45 minutes

Students in Action

Today I am starting this lesson with a video from the Scholastic website - Study Jams. I have two reasons for selecting this video as an introduction. First it has a nice explanation of kinetic and potential energy and our question for today is, "What is the relationship between kinetic and potential energy?"  I also want to introduce this website to students. The site has many videos on math and science that students may use as a resource to clarify their understanding.

This is our first year with 1-to-1 computers for students and I want to help them develop a selection of go to informational resources at a variety of grade levels and media types. I will also include a link to this website in my Moodle LMS for this class so students who are absent will have an introductory resource to jump start their progress on this lesson. 

Link to Study Jam 

We answer the challenge questions at the end of the video together as a class. 

Next, students answer questions 1,2 and 3 on their lesson sheets for today with their elbow partner. The strategy is Turn/Talk/Record. Students are discussing the questions together and being help accountable for their discussion by recording their answers. Before going to the website, I ask students to share out their answers to questions 1, 2 and 3. This is a mini formative assessment to see if students need more support to build adequate background knowledge before continuing to independently explore the simulation using the lab sheet as a guide as they work through the simulation.  Middle school students bring a wide range of background knowledge from elementary school so this step is a helpful probe to check for understanding. 

PhET Simulation Link

We use the HTML5 version of the simulation. This format works on both PCs and IOS devices. It also does not require a download so we do not have to work about problems downloading a Java version.

In this video, I share how I model using the simulation for students and take a look at student response expectations and steps taken to encourage student growth in developing more robust responses to question probes as they evaluate their data collection.

As students work through the lesson, I circulate through the classroom to be sure the settings are correct and they are collecting the appropriate observations and using evidence from these observations to support their conclusions.

Connecting the Learning

10 minutes

I hand out pullback cars, masking tape, toy car tracks and meter sticks for student exploration. 

Students have fun while they explore how changing the amount of potential energy changes the amount of kinetic energy in these toy cars.

Connecting a virtual experience with a hands-on activity helps reinforce learning.

Students need this free play with the pullback cars before we embark on a full scale experiment. Many of the students do not have experience with this type of toy. Their exploration in this lesson will help prepare them to write an experimental question and hypothesis.

Here is a short video of students in action. They used the plastic tracks to help the pullback car travel straight.