SWBAT design an experiment demonstrating the relationship between the potential and kinetic energy using pullback cars and report their findings by graphing averages.

Toys are great tools for learning about physical science. What can you learn by playing with pullback cars? How can you use math to demonstrate relationships?

Students need to conduct their own investigations. They need to be able to ask a question and systematically proceed to answer that question with an investigation of their own. This lesson provides students with a guided opportunity to design their own investigation of the relationship between potential and kinetic energy.

At my school, all students are required to participate in a science fair. I want my students to practice designing experiments with my guidance throughout the school year so they are well prepared to tackle the science fair challenge.

This experimental design does not include all the elements of a science fair. That would simply take too much time from our schedule.

Students will focus on identifying key elements of an experiment; question, controls, independent and dependent variables and an hypothesis. They will design a table to collect data, graph their data using excel and create a document with the graph embedded and a summary of their findings.

The materials are provided for the students. The procedure is simple so we will focus on writing procedures in another lesson.

5 minutes

Students have already completed the lesson - Exploring the Relationship Between Potential & Kinetic Energy. This lesson challenges the students to apply their understanding of potential and kinetic energy to a new situation. Students will design an experiment using pullback cars to demonstrate the relationship between potential and kinetic energy. (**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.*)

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 applying knowledge gained through interaction with a simulation to the physical objects, in this case pullback cars, students deepen their understanding, and are developing mastery as they use the simulation as an iterative process. (**SP2** - *Using Models*)

Data collected from the pullback car experiment allows students to develop a graph to visualize the relationship between kinetic and potential energy. (**MP2** - *Reason abstractly and quantitatively*) Students are applying math skills to enrich their understanding of physical science. (**MP4** - *Model with mathematics*)

Students are beginning their path towards mastery as they apply the process of developing an experimental investigation to demonstrate the relationship between the potential and kinetic energy of pullback cars. (**SP3** - *Planning and Conducting Investigations*)

The lesson asks students to collection observations in a table, graph the averages and use that information to state conclusions about their investigation. They are developing perseverance by evaluating the data collected and drawing conclusions about the big ideas represented by their data. (**SP8** -* Collecting and Communicating Information*)

Students communicate their findings using the graph they created as a visual representation of experimental results. They summarize their findings representing specific data points on the graph as evidence. (**7.RP.A.2.D** - E*xplain what a point (**x, y) on the graph of a proportional relationship means in terms of the situation, with special attention to the points (0, 0) and (1, r**) where r is the unit rate.*)

By integrating graphs into their explanations of the experimental results, students are demonstrating how visual displays can strengthen their evidence. (**SL.8.5 **- *Integrate multimedia and visual displays into presentations to clarify information, strengthen claims and evidence, and add interest*.)

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

90 minutes

*Students in Action*

At the end of the lesson - Exploring the Relationship Between Potential & Kinetic Energy - I gave the students pullback cars to explore. I explain to students when you pull the toy car backwards on a flat surface, an internal spring is wound creating potential energy. Then when the car is released, the spring unwinds producing kinetic energy.

Today I am asking students to design an experiment demonstrating the relationship between potential and kinetic energy using these same pullback cars.

As I watched the students test the toys earlier, I saw that if they pulled back the cars more than a few inches, they flew forward out of control. So I am providing students with plastic toy car tracks to help them control the cars. I also ask the students if it is necessary to pull back the cars more than just a few inches to demonstrate potential and kinetic energy. They agree that a few inches will work and it would be easier to control and measure results.

Students are responsible for stating a question, writing a hypothesis, identifying independent and dependent variables as well as experimental controls. For this experiment we are identifying controls as what we will keep constant during the experiment so that results can be compared.

Students work with a partner to compete the Overview of Your Experiment Document. Students are also required to develop a data collection table for their experiment.

Students have used this document in the past to write an overview of their experiment. We are using the document as a planning guide today. Students are not expected to write a formal overview of their experiment. The main student deliverable in this lesson is the graph and evaluation of the test results the graph represents.

The document must be completed before students are given materials and permission to test.

This short video was created to show my students how to use excel to enter their data, create a graph and copy the graph and table into a word document so they can comment on what the graph shows. I post this video on my classroom website so students can refer to it as needed throughout the year.

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