The classroom is abuzz. Students

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1 Ideas and techniques to enhance your science teaching Chemical Reaction Vehicles A STEM project takes off in fifth-grade classrooms. By Wendy Smith and Jesse Meyer The classroom is abuzz. Students surround the test track, craning their necks for a better view. An engineering team works together to load chemicals, add water with a syringe, quickly fix a cork into the bottle, and position their chemical reaction vehicle against the wall. They step back and crouch low as pressure builds in the chamber. Some children cover their ears in anticipation. One member of the team lies down on the floor, peering through her goggles to determine if there is a leak. Suddenly, a loud pop explodes and the car is propelled forward while children scream in surprise or cheer the success of their classmates. As the boy and girl measure the distance their vehicle traveled, they discuss how to adjust the amount of chemicals to improve its performance, and a new team prepares for the next test. The joy and excitement about science and engineering is audible throughout the afternoon. The fifth-grade students at Hong Kong International School have been learning about the structures and properties of matter for many years, but two years ago the teachers added an engineering design challenge to provide them with the opportunity to apply their understanding of how matter behaves and changes to solve a problem. The chemical reaction vehicle design challenge was the culminating experience in a unit called Structures and Properties of Matter. During this unit, students explored basic properties of matter, various physical changes of matter, and indicators of chemical changes. In the preface of the book The Essential Engineer: Why Science Alone Will Not Solve Our Global Problems, Henry Petroski (2010, p. IX),... seeks to illuminate the differences between science and engineering and thereby clarify their respective roles in the worlds of thought and action, of knowing and doing. Petroski argues that it is the interaction of both science and engineering that is necessary to solve critical global issues including climate change and clean, renewable energy sources. Engineering is, then, the application of what we know about science. The Next Generation Science Standards (NGSS) echo Petroski s ideas. A Framework for K 12 Science Education (NRC 2012) notes that students deepen their understanding of science by applying their knowledge to engineering and technology to solve practical problems. Both positions converge on the intention of integrating technology and engineering into the science curriculum so students feel empowered to use what they learn in their everyday lives. PHOTO COURTESY OF THE AUTHOR Students design their own vehicles to test. Introducing the Challenge The engineering design challenge presented to students required them to use their...knowledge of science to help design and build a vehicle that is powered solely by a chemical reaction. Once the project was introduced, the students shared their November

2 understandings of the challenge and formulated questions to clarify misunderstandings. Some questions included: What materials can we use? How do we make a chemical reaction? Can we use a toy car that we have at home? How much time do we have to do the project? Can we pick our partners? Next, the teachers presented the criteria and constraints in order to answer the students questions and to provide clarification (Figure 1; See NSTA Connection for project introduction). The decision regarding how partnerships were created was left up to FIGURE 1. Project criteria and constraints. Criteria Vehicle must travel at least 1 m. Constraints Vehicle must not exceed 30 cm. Vehicle must be constructed using available materials (no toy cars). Chemical reaction must occur from combining the substances and water available in the classroom. Once the chamber for the reaction is chosen, no changes can be made to that part of the design. The vehicle testing area. individual teachers. Some chose to assign partner groups, while others let the students decide. The timeline for the project was also determined by each classroom teacher, with some preferring to do the project over three to four days with two to three hours of project time each day, while others completed the project over two weeks with approximately one hour of project time each day. Parts 1 and 2, described below, take approximately equal amounts of time. While all the students at our school had experience in previous grades with engineering design challenges, the teachers felt that a quick refresher on the process prior to starting the project would benefit students. Crash Course Kids, a You- Tube channel focusing on elementary science, has a series of short, engaging videos on an engineering design process. Teachers shared the episode, The Engineering Process: Crash Course Kids #12.2. Students discussed the video and compared the steps shown to the steps we use universally in our school: Ask, Imagine, Plan, Create, and Improve (see Engineering is Elementary under Internet Resources). Students were required to document their scientific and engineering work in their lab notebooks. Students used a checklist in order to keep track of project guidelines and assessment criteria (see NSTA Connection). Getting Down to Work The project was composed of two parts. Part 1 focused on the application of science and Part 2 focused on engineering design. The project was split into two parts after the first year of implementation because the teachers observed that when the project was open-ended and students had more flexibility in how they approached the challenge, students tended to focus more on the design 72 Science and Children

3 Two students prepare their vehicle for testing. of the vehicle chassis and less on the chemical reaction intended to provide its power. They also noticed that the students approaches to solving the problem were poorly planned and unstructured, most often due to the inherent excitement of getting to make chemicals react. The teachers revised the unit to strengthen the logical connections between what students discovered while testing the chemical reaction chamber and in designing an effective vehicle on which it could be mounted. Part 1: The Application of Science During Part 1 of the project, students figured out the most effective combination of substances and water in their chamber to create a reaction to propel the vehicle forward. Available materials included: Citric acid Baking soda Water Coffee filters Soda bottles of various sizes Film canisters A variety of smaller, plastic, narrow-mouthed bottles Corks Rubber stoppers Many students wanted to use vinegar as part of their chemical reactions due to a previous exploration in the science lab. However, the teachers prohibited this material due to its cost as well as to the challenges associated with maintaining a clean classroom environment. Students were permitted to bring bottles from home for their chamber prototypes as long as they met the criteria for size and were deemed safe to use. Teachers and students agreed on safety protocols prior to the start of the project. For instance, they concluded that safety goggles should be worn at all times while working with the substances. Additionally, the testing area was cordoned off to ensure that only the group testing could use the space. Finally, it was agreed that the teachers would approve investigation plans before testing to ensure safe and reasonable amounts of substances were being used. Teachers then modeled how to effectively clean and dry the testing area after each trial using buckets of water, sponges, and dry towels. For more information on chemical safety, visit the NSTA Safety in the Science Classroom website (see Internet Resources). Before the start of the project, students conducted an investigation into chemical reactions to determine whether or not mixing two or more substances resulted in a new substance. Teachers modified an existing lesson from The Institute for Inquiry, a professional development program from the Exploratorium (see Internet Resources). Students set up investigations to discover chemical reaction indicators. They deduced that the appearance of new substances is indicated by color change, temperature variations, and/or gas formation (see student instruction sheet titled Changes online; see NSTA Connection). Gas formation resulting from the combination of two or more substances became the driving force in the students application of science to solve the design challenge. Next, all students began by placing 5 g of baking soda and 5 g of citric acid in an 8 oz. plastic cup and added 50 ml of room-temperature water. Observations were shared and the teachers led a discussion about the variables. Variables identified by the students included: container for the reaction amount of water amount of baking soda November

4 amount of citric acid temperature of water Students discussed how they could change only one variable at a time to try and figure out the most effective combination of substances and water to use in a given chamber to create a chemical reaction that would propel the vehicle forward. Students realized that they could change the container for the reaction and keep all the other variables the same (5 g baking soda, 5 g citric acid, 50 ml water). While the temperature of the water is a variable, the difficulty of keeping temperatures constant during testing would prove to be too difficult, so students were limited to using room-temperature water for all investigations. Each group decided on the most effective prototype and began testing the chemical reaction to propel the chamber forward. Distances for each of the three trials were measured and recorded in notebooks. After round one, students shared their results with the class. Then they compared the data collected by different groups regarding the relationship between the volume of the chamber and the distance it traveled and contrasted it with their own results. The analysis of data by the class was used to inform the next round of investigations. While students understood the necessity of changing only one variable at a time, teachers did find that when partner groups shared their testing results with the class, they often did not incrementally change the amounts of the substances to be used. The initial investigation started with 5 g each of baking soda and citric acid, and in the second investigation some students wanted to jump up to using 20 g or more of a substance. Conversations ensued regarding the benefit of making incremental changes to identify cause-and-effect relationships. In addition to realizing the importance of incremental change, students realized relationships between chamber volume and amount of substances used to create a reaction. Students had approximately four to five hours to develop and test the amounts of the substances and water to create the chemical reaction in the chosen chamber. Throughout the testing phase, students continually shared results, compared and analyzed data, and used the findings and observations of other teams to guide their investigations. They quickly discovered several cause-and-effect relationships, including how the volume of the chamber affects the pressure of gas formation inside, how the tightness of the cork affects the propulsion from the reaction, and how the starting position of the chamber A student records data about his vehicle. either against a wall or not affected the distance traveled. Students documented all of their work for Part 1 in their lab notebooks and used the project checklist to guide their work. Once the students finalized the chamber and the exact amount of substances to create the chemical reaction, no changes were allowed to that part of the vehicle. Part 2: Engineering Design Process During Part 2 of the project, students used an engineering design process to create a chassis that incorporated the chemical reaction chamber. Materials provided for use of the vehicle included but were not limited to: Cardboard Aluminum foil CDs Toilet paper and paper towel 74 Science and Children

5 tubes Wooden skewers and dowels Straws Various Lego pieces Students brought additional materials from home to build their vehicles as long as they were not premade toy cars. The teachers wanted students to have experience building a vehicle designed for the chamber they tested. To launch Part 2, the students individually brainstormed vehicle design ideas and then shared ideas with their partners. Models of the designs included labels of materials used and placement of the chamber on the chassis. Partners discussed possible pros and cons of each design and together decided on the initial prototype to be constructed. Depending on the materials and prototype design, some groups quickly constructed an effective prototype, while others discovered that it was difficult to design a vehicle with wheels that spin freely. The teams that encountered this failure looked at the designs of other teams, observed how the wheel and axle system on toy cars work, and drew revised models of the vehicle designs in their notebooks. Some teams bypassed the traditional vehicle chassis, changing their designs to sleds and thus eliminating the need to build a wheel and axle system. Once the vehicle chassis was built, the chamber connected, and substances and water added, groups tested the overall effectiveness of the design. Distances were measured and observations were recorded for multiple trials to serve as evidence to guide in the improvement of the vehicle. Since one of the constraints of the challenge stated, Once the A student shares his data with the class. chamber for the reaction is chosen, no changes can be made to that part of the design, all improvements in this stage of the project were focused on the vehicle design and no longer on the chemical reaction inside the chamber. Many students identified the cause-and-effect relationship between the weight of the chassis and the chemical reaction s ability to power the vehicle. As a result, groups modified their chassis by streamlining their designs or making other modifications to the wheel design, chamber position, or variables related to steering the vehicle in a straight line. Multiple design solutions to address a specific failure point were tested in order to determine which best met the criteria. For example, one group adjusted the angle of the chamber mounted on the chassis three different ways, facing up 30 degrees, horizontal, and facing downward 30 degrees, to determine which angle would best propel the vehicle forward. Students continued to document their work in the lab notebooks using the project checklist to make sure all important components were included in their writing. Teachers periodically displayed varied examples of lab notebooks in order for students to self-reflect and to help guide them toward successful documentation of their work. On Your Mark, Get Set, Go! The day of final testing was full of energy, excitement, and anticipation. Students enjoyed viewing and discussing each other s final vehicle designs between launches. Loud pops, screams of surprise, laughter, and words of encouragement and congratulation were constant for the duration of the testing day. While not all groups met the criteria of having their vehicle travel a full meter, they were still successful because they created chemical reactions in the chamber to move the vehicle some distance. More important than the actual distance the vehicle traveled was the students experiences with the iterative design process and as both scientists and engineers. In the early stages of the testing, many groups failed November

6 to launch vehicles. This provided opportunities for teachers to coach students on ways to analyze every attempted launch to search for ways to redesign vehicles. In cases like this, students often discovered that corks were fixed too loosely, gas formed before the stopper was pushed on, or not enough chemicals were added for enough gas to form and build pressure. In each case, students returned to their notebooks, discussed modifications, sketched ideas, and rebuilt their vehicles. Often, students returned to test again and either solved the distinct engineering problem identified before or analyzed and returned to the drawing board. Having ample time for students to discover possible problems and brainstorm solutions was integral to their working as scientists and engineers in an authentic way. Assessment Both students and teachers assessed using the project checklist. Students recorded the page numbers from their lab notebooks that illustrated each point on the checklist, including how their vehicles met the criteria and constraints. They also completed a self-reflection form (see NSTA Connection) in order to capture their perceptions on how well they felt they learned key disciplinary core ideas, science and engineering practices, and schoolwide goals of resiliency and collaboration. When teachers assess the students, they should consider the Application of Science and Engineering Design Process sections of the chemical reaction vehicle checklist and related documentation in the student notebooks to determine whether or not learning goals were met. Teachers that have implemented this project noted that some groups met the learning goals of the project even though their vehicles did not travel one meter. In addition to the notebook and checklist, anecdotal observations during the project should provide teachers with the evidence required to make summative assessments of student learning. Students Erik and Michelle summed up the experience when they reflected that, Even though our car failed three times, on the fourth time we got it to go more than three meters. We didn t fail three times, we succeeded once. After the fourth time, we finally made the chemical reaction work. We learned from making a ton of mistakes, and we made it better. Modifications Some students may struggle in Part 1 to complete a functioning vehicle and engine. To ensure students have adequate opportunities to meet the standards, teachers may consider providing some students with pre-built or designed components. Toy cars onto which a engine could be mounted, an engine design that is known to work well, or a combination of both devised by the teacher may be helpful for students with certain constraints. In Part 2, the teacher might suggest amounts of chemicals for starting points and help students develop and record appropriate increments. Modifications to Parts 1 and 2 as outlined will help scaffold the learning experience for students in some classrooms while still allowing for the sense of excitement and discovery inherent in the project. While interacting with and observing students at work, the teachers developed several ways to differentiate the project. First, they noticed that in their attempts to make the vehicles go as far as possible, students were using greater quantities of the chemical materials quickly, resulting in shortages. The teachers suggested adjusting the criteria from Vehicle must travel at least 1 meter in distance to Vehicle must travel between 1 and 2 meters in distance. Not only would this constraint limit the use and waste of resources, but it would also increase the level of difficulty and precision required by the students. Next, teachers considered adding an element of economics to the project in order to help students consider the amount of materials being used. In this way, the most successful vehicles would be the ones that not only met the criteria for success by traveling at least a meter but also did so with the most economic efficiency (i.e., used the least amount of materials). Both suggestions for improvement would save money and materials for the school and increase the challenge level in the project for the students. Finally, the teachers noticed that some teams vehicles failed to reach the one meter distance in the criteria. However, the teams still met the performance expectations by designing and testing prototypes as well as conducting investigations into chemical reactions. For students with special learning needs, modifying the criteria may be required. Final Thoughts The chemical reaction vehicles project was a success in many ways. Teachers noted highly engaged stu- 76 Science and Children

7 Connecting to the Next Generation Science Standards (NGSS Lead States 2013): 5-PS1 Matter and Its Interactions 3-5 ETS1-1 Engineering Design The chart below makes one set of connections between the instruction outlined in this article and the NGSS. Other valid connections are likely; however, space restrictions prevent us from listing all possibilities. The materials, lessons, and activities outlined in the article are just one step toward reaching the performance expectations listed below. Performance Expectations Connections to Classroom Activity Students: 5-PS1-4: Conduct an investigation to determine whether the mixing of two or more substances results in a new substance. 3-5 ETS1-3: Plan and carry out fair tests in which variables are controlled and failure points are considered to identify aspects of a model or prototype that can be improved. Science and Engineering Practices Planning and Carrying Out Investigations Analyzing and Interpreting Data Disciplinary Core Ideas PS1.B: Chemical Reactions When two or more different substances are mixed, a new substance with different properties may be formed. ETS1.C: Optimizing the Design Solution Different solutions need to be tested in order to determine which of them best solves the problem, given the criteria and the constraints. Crosscutting Concept Cause and Effect conducted an investigation to determine the indicators of a chemical change, including color change, temperature change, and/or gas formation. conducted tests to determine vehicle distance traveled based on variables of design and chemical reaction chamber. Failure points were identified and multiple solutions were tested in order to improve vehicle design. conducted fair tests of combinations of substances in the chamber and vehicle body design, measured the travel distance, and recorded data. compared and contrasted all group data, discussed similarities and differences in their findings, and used data from all groups to make revisions to both the chamber and vehicle design. identified indicators of chemical changes when two or more substances are combined, including temperature change, color change, and/or gas formation. analyzed all team results, modified vehicle design to optimize performance, and tested vehicle to determine results. identified cause-and-effect relationships between the substances used in the chamber and the effectiveness of the gas formation as well as the relationships between failure points, vehicle design, and human error. November

8 dents experiencing the interaction of science and engineering as well as the opportunity for children to think creatively, work collaboratively, and develop resiliency when challenged with difficult work. The energy in the classroom throughout the week, from introduction to design to testing, built steadily like the pressure in the vehicle chambers, propelling student learning and collaboration forward at an explosive speed. Wendy Smith gmail.com) is a STEM specialist, and Jesse Meyer (jmeyer61@ gmail.com) is a fifth-grade teacher, both at the Hong Kong International School. References National Research Council (NRC) A framework for K 12 science education: Practices, crosscutting concepts, and core ideas. Washington, DC: National Academies Press. NGSS Lead States Next Generation Science Standards: For states, by states. Washington, DC: National Academies Press. Petroski, H The Essential Engineer: Why science alone will not solve our global problems. New York: Alfred A. Knopf. Internet Resources Engineering is Elementary: Engineering Design Process The Engineering Process: Crash Course Kids # kU Exploratorium s Institute for Inquiry NSTA Safety in the Science Classroom NSTA Connection Download the project introduction, student instruction sheet checklist, and selfreflection at SC1711. Share Your Ideas! NSTA s CONFERENCES ON SCIENCE EDUCATION To submit a proposal, visit Have an idea for an inspiring presentation or workshop on science or STEM education? Submit a session proposal today for... 7th Annual STEM Forum & Expo, hosted by NSTA Philadelphia, PA...July (2018) 2018 Area Conferences Proposal Deadline: 12/4/2017 Proposal Deadline: Reno,NV...October /16/2018 Gaylord Nat l Harbor, MD...November Charlotte, NC...November 29 December National Conference St. Louis, MO...April Proposal Deadline: 4/16/ Science and Children