Science of Speed by Blue

UST

Blue

Science of Speed (SOS) Pitsco, 2002; revision in progress (anticipated 2015) The Science of Speed is messy, loud, deliberate, engaging, and fun. Itâ&#x20AC;&#x2122;s all about getting a gilded piece of wood down a 65-foot, 7.5-inch track quickly. Very quickly. The design is on wheels and is propelled by a compressed CO2 cartridge. The Science of Speed, which is based on national standards, is intended for middle school students studying mathematics, technology, and/or science. With little effort the materials can be made appropriate for younger students, and with slight modifications the materials can be appropriate for a high school physical science or physics class. http://www.science-of-speed.com

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The Science of Speed

A Physical Science Investigation Performance Assessed Inquiry: Volume 1

Teacher’s Guide

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Written by Brad Blue

All rights reserved. This product and related documentation are protected by copyright and are distributed under licenses restricting their use, copying, and distribution. No part of this product or related documentation may be reproduced in any form by any means without prior written authorization of Pitsco, Inc. The Science of Speed™, PowerPak™, and Zoon™ are trademarks of Pitsco, Inc. All other product names mentioned herein might be the trademarks of their respective owners. www.pitsco.com

Contents

A PERSONAL NOTE .......................................................................................................... 5 OVERVIEW ....................................................................................................................... 5 Introduction................................................................................................................. 5 Standards .................................................................................................................... 6 Integrated/Interdisciplinary........................................................................................ 6 The Need for Lifelong Kindergarten........................................................................... 7 Shifting Paradigms in Middle Schools........................................................................ 8 Materials/Resources ................................................................................................... 8 Time Estimate.............................................................................................................. 9

PROGRESSION: DESIGN TO PERFORMANCE .................................................... 10

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PHASE 1: ZOON AIR CAR AND PRELIMINARY ACTIVITIES .............................................. 10 Zoon Air Car ......................................................................................................... 10 Display Class Materials ........................................................................................ 11 Preparation ............................................................................................................ 11 Materials List ........................................................................................................ 11 The Science of Speed Trailer Video ..................................................................... 12 Distribute............................................................................................................... 12 Construct Zoon Air Car ........................................................................................ 12 Query the Class ..................................................................................................... 12 Instruction ............................................................................................................. 13 Extended Activities............................................................................................... 14 PHASE 2: DESIGN − GRAPHICS AND LAYOUT ................................................................. 15 Preparation ............................................................................................................ 15 Optional................................................................................................................. 15 View...................................................................................................................... 15 Overview............................................................................................................... 16 Thumbnails ........................................................................................................... 16 Design Sketch ....................................................................................................... 16 Scale Design.......................................................................................................... 16 PHASE 3: DESIGN PHASE – GO/NO GO .......................................................................... 18 Extended Activities............................................................................................... 19 PHASE 4: CAR CONSTRUCTION − FROM DESIGN TO MODEL ........................................... 19 Preparation ............................................................................................................ 20 Materials List ........................................................................................................ 20 Optional................................................................................................................. 20 Tools and Wood Materials.................................................................................... 20 Essential Tools: Balsa ........................................................................................... 21 Essential Tools: Basswood ................................................................................... 22 Tool List (Ideal) .................................................................................................... 22 View...................................................................................................................... 23 Redistribute ........................................................................................................... 23 Prototype ............................................................................................................... 23

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Construction.............................................................................................................. 24 Redistribute ........................................................................................................... 24 Transferring the Design to the Body Blank .......................................................... 24 Drilling the Axle Holes......................................................................................... 25 Cutting the Wood.................................................................................................. 25 Sanding/Contouring .............................................................................................. 25 Inevitable Mistakes Along the Way...................................................................... 25 Pretrial Assembly...................................................................................................... 26 Distribute............................................................................................................... 26 Assembly Procedures............................................................................................ 26 PHASE 5: COLLECT DATA − MEANINGFUL MEASUREMENTS ......................................... 26 Preparation ............................................................................................................ 27 Equipment List...................................................................................................... 27 View...................................................................................................................... 27 Distribute............................................................................................................... 27 Activities ............................................................................................................... 27 Managing the Activities........................................................................................ 28 Extended Activities............................................................................................... 28 PHASE 6: TRIAL PHASE – GO/NO GO ............................................................................. 29 PHASE 7: TRIAL RACES − PERFORMANCE ...................................................................... 29 Preparation ............................................................................................................ 29 View...................................................................................................................... 30 Race and Record Times ........................................................................................ 30 Collect All Cars..................................................................................................... 30 PHASE 8: COLLECT DATA – MATHEMATICAL INFORMATION ......................................... 30 Preparation ............................................................................................................ 30 View...................................................................................................................... 31 Distribute............................................................................................................... 31 How Fast is Fast: The Mathematics of CO2 Speed .................................................. 31 PHASE 9: ANALYZE DATA − INTERPRETATION .............................................................. 32 Preparation ............................................................................................................ 32 Recommended Materials ...................................................................................... 33 View...................................................................................................................... 33 Instruction ............................................................................................................. 33 Query the Class ..................................................................................................... 33 Distribute............................................................................................................... 34 PHASE 10: PROPOSE TECHNICAL CHANGES – TECHNICAL WRITING .............................. 35 Preparation ............................................................................................................ 35 Recommended Materials ...................................................................................... 35 View...................................................................................................................... 35 Distribute............................................................................................................... 35 Instruction ............................................................................................................. 35 Query the Class ..................................................................................................... 36 Demonstration....................................................................................................... 36 Mass of Compressed CO2 ..................................................................................... 37 PHASE 11: DESIGN MODIFICATIONS & DETAIL − IMPLEMENTATION ............................. 37 Preparation ............................................................................................................ 37

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Tool List (Ideal) .................................................................................................... 38 Paint Supplies ....................................................................................................... 38 Optional Supplies.................................................................................................. 38 Equipment List...................................................................................................... 38 View...................................................................................................................... 38 Redistribute ........................................................................................................... 39 Reassembly ........................................................................................................... 39 Extended Activities............................................................................................... 39 PHASE 12: RACE-READY PHASE – GO/NO GO ............................................................... 39 View...................................................................................................................... 39 Distribute............................................................................................................... 39 PHASE 13: DESIGN AND AESTHETIC JUDGING − PEER EVALUATION .............................. 40 PHASE 14: A DAY AT THE RACES − PERFORMANCE....................................................... 41 Preparation ............................................................................................................ 42 View...................................................................................................................... 42 PHASE 15: COLLECT DATA ............................................................................................ 42 Preparation ............................................................................................................ 42 Distribute............................................................................................................... 42 PHASE 16: FINAL SUBMISSION − PORTFOLIO IS COMPLETE ........................................... 43

A Personal Note

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The Science of Speed grew out of years of piecing together science and mathematics curricula that answer the arduous challenges of delivering stimulating science and mathematics experiences to an increasingly diverse population of middle school students. One of the most successful examples of this type of instruction is “A Day at the Races,” which has been integrated as part of this curriculum. For years, Pitsco has provided outstanding materials and resources for CO2 racing. Most of the items are exclusive to Pitsco. What I needed, however, was a curriculum that exploited the materials and resources and unified the experience of designing, building, testing, and documenting CO2 dragsters. I am very grateful for Harvey Dean’s (CEO and founder of Pitsco) vision and invitation to create a product that is standards-based, engaging, multidisciplinary, event-based, and fun. The support and technical staff at Pitsco are paragons, second to none, knowledgeable, and pleasant. If you have come this far − and you have, if you are still reading − you have a cadre of support and another great learning tool for your instruction. Last, I would be remiss not to mention that without the enduring commitment of many colleagues, I would have lost more of my mind along the way. Many of these colleagues shaped the ideas herein and made The Science of Speed all the better. They know their names. Thanks. − Brad Blue

Introduction

Overview

The Science of Speed is messy, loud, deliberate, engaging, and fun. It’s all about getting a gilded piece of wood down a 65-foot, 7.5-inch track quickly. Very quickly. The wood is on wheels and is propelled by a compressed CO2 cartridge. A renewable energy! I have heard students refer to The Science of Speed as the Pinewood Derby on steroids! The Science of Speed is intended for middle school students studying mathematics, technology, and/or science. With little effort the materials can be made appropriate for younger students, and with slight modifications the materials can be appropriate for a high school physical science or physics class. The Science of Speed is not for the faint of heart. Like any good experiment or investigation, your reflective, marginal notes will be replete with: “the next time I do this . . .” But there is a correlation between your efforts and student success. The Science of Speed will require effort on your behalf, especially the first year.

The gains are exponential: students are engaged, data is relevant, parents are well aware of what is happening at school. The Science of Speed is eventbased and has curb appeal. It’s fun. Word in the halls will reach you, and younger students will ask whether they will design and race when they enroll in your class. Be sure to invite them to the races! Principally, this investigation centers on the physical sciences and includes sufficient structure for the teacher and students to ensure success; yet the parameters are sufficiently broad that all students are engaged. The Science of Speed works well in a heterogeneous class of students. A plethora of options; the use of tools, technology, and peer evaluation; and a culminating event, A Day at the Races, are the main ingredients. There’s no single solution to the challenge, although there are parameters.

Standards

Integrated/Interdisciplinary

The well-articulated math, science, and technology standards provide a vision of learning and teaching mathematics, science, and applied technology. Appendix A references the standards; it is hoped that the format of the appendix is user friendly and helpful when you plan instruction, design curriculum maps, or work with colleagues in mathematics, technology, and writing.

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The Science of Speed integrates physical science, mathematics (data collection, analysis, and graphing), technology, and language (technical writing). The discrete disciplines use the design, building, testing, and racing as core experiences. A self-contained teacher (science, mathematics, and so forth) can deliver all the elements or work with colleagues and employ a team approach. The language (English) teacher could use the writing prompt, “Technical Changes Sheet,” to develop technical writing skills. Similarly, the mathematics of data collection, analysis, and graphing are all the more meaningful when the data is relevant to the student. Effectively, a collegial approach has three advantages: • Collegiality strengthens the instruction. Each teacher brings strengths to the investigation. • Collegiality lightens the load. The time on task is shared so that no one teacher is responsible for all elements. The science teacher, for example, has more time to engage students in science because the language teacher is managing the technical writing component. • Collegiality strengthens teams. If teachers are working on a common investigation, dialogue is frequent and meaningful. We learn from one another. We are more likely to share student learning. We interact more often and more meaningfully. Students will see and, perhaps, emulate this team approach.

The Need for Lifelong Kindergarten

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Mitch Resnic* has suggested that education needs to look at kindergarten as the paradigm for educational experiences. Following the long tradition beginning with Froebel (following Pestalozzi), Resnic argues that children need to learn through their senses and through physical activity. Froebel’s 20 gifts, including manipulative materials such as blocks and balls, have been given to kindergartners around the world for generations. Everyone loves kindergarten! The classrooms are alive, full of color, textures, and purposeful (most of the time!) activities. Why, then, is this successful model and pedagogy abandoned subsequently, beginning in first grade? These observations are more than comments about learning styles; they have everything to do with common sense. Why abandon an effective pedagogy so that by the time students arrive in middle school, the classroom is bereft of the original gifts or the dynamic equivalents? In fact, rather than adding to the repository year by year based on the developmental abilities of students, we take the few gifts from kindergarten and replace them with archaic structures that have never served good pedagogy. The transition into high school is no better. In fact, many students are tracked into “higher” math and science based on their ability to survive without making things; in other words, they are willing to think conceptually and hypothetically without reference to the senses – things they can see, hear, touch, and so forth. Other students are relegated to the nonacademic tracks of applied math, consumer science, and such, without having the opportunity to be involved in the “advanced,” more conceptual courses. The Science of Speed is a deliberate attempt to introduce new “gifts” with the view that all students will have the opportunity to make ideas instead of trying to get ideas. Young learners need things before words and the concrete before the abstract. This is commonly referred to as constructivism. Most of the gifts, or tools, are common: drills, sanders, sandpaper, graph paper, scroll saws, and so forth, and others are cutting edge: wind tunnels, photo gates, simulation software, and so forth. The Science of Speed is a modest attempt to bring together the best of the old and the new. *Note: For more information, see Mitchel Resnic’s Technologies for Lifelong Kindergarten, Educational Technology Research & Development. Volume 46, Number 4 (1998); also at http://mres.www.media.mit.edu/people/mres/.

Shifting Paradigms in Middle Schools

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Industrial technology shops such as woods, metals, and mechanics are all but gone in most middle schools. New, digital technologies have yielded modular labs, replete with simulations and higher tech equipment such as Pitsco’s Synergistic Systems (middle level) and Pathways (high school). Shop teachers have been replaced, usually through attrition, by technology teachers. The focus has shifted from hands-on to simulations and Web-based experiences. These new solutions are engaging and have proven to increase student interest and learning. So instead of making a cabinet or gun rack, students are creating Web pages, designing with CAD software, and operating CNC equipment. In some instances the old and the new coexist, usually older schools with shop facilities and a staff that is moving in the direction of digital bytes. This is the best of both worlds. But most new schools are not designed for shops and technology labs. Physical space, class schedules, and staffing do not afford the old and the new. Effectively, the drills, saws, and lathes are displaced, and students have little or no access to them. The tools are migrating from the old shops to make room for modular labs. In some instances, science teachers are adopting them, integrating them into their curriculum. For example, students build birdhouses, which requires saws and drills, while studying habitats in life science. The Science of Speed encourages the science teacher to integrate the older and the newer technologies: drills are essential and wind tunnels are beneficial for data collection. The industrial technology teacher has the advantage of living in both worlds: hands-on and newer digital technology. Ideally, the science and technology teachers will work collaboratively with the mathematics and language teachers.

Materials/Resources

The following printed materials − excluding the first two items listed − are included as blackline and/or color masters − in this teacher’s guide. They are referred to throughout the teacher’s guide. • Portfolio (student folder) • Zoon Air Car parts card • Zoon Air Car instructions • “Checklist” • “Thumbnail Drawing Sheet” • “Design Sketch Sheet” • “Design Phase Data Sheet” • “Design Rules & Specifications” • “4 -View Design” • Grid paper (11" x 17") with metric ruler • “Trial Phase Data Sheet” • “Race Time Sheet”

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“Posttrial Phase Data Sheet” “Graph Data Sheet” “Technical Changes Sheet” “Race-Ready Phase Data Sheet” “Final Data Sheet” Sample race brackets

The CO2 dragster materials are available from Pitsco. I recommend the Dragsters Getting Started (GS) Package if this investigation is new to you. The GS Package includes everything you will need for 50 cars with two exceptions: • You will need additional CO2 cartridges because those shipped with the GS Package will be used during the trial phase. • Polystyrene car blanks are used for designing prototypes (see Phase 4, Car Construction). These polystyrene blanks as well as the foam cutter can be ordered from Pitsco (visit www.shop-pitsco.com).

Time Estimate

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Note: The following estimate of class time needed to complete The Science of Speed curriculum depends on several variables: ! Wood type; for example, balsa is easier to cut than bass. ! Number of tools available. ! Age and experience of students. ! Familiarity with The Science of Speed; this estimate assumes that the materials are new to the teacher and students. • Phase 1: Zoon Air Car and Preliminary Activities − 5 hours • Phase 2: Design (graphics and layout) − 4 hours • Phase 3: Design Phase − Go/No Go − 1 hour • Phase 4: Car Construction − 5 hours • Phase 5: Collect Data − 1 hour • Phase 6: Trial Phase − Go/No Go − 1 hour • Phase 7: Trial Races − 1 hour • Phase 8: Data Collection − 1 hour • Phase 9: Data Analysis − 2 hours • Phase 10: Propose Technical Changes − 2 hours • Phase 11: Design Modifications and Detail − 4 hours • Phase 12: Race-Ready Phase − Go/No Go − 1 hour • Phase 13: Design and Aesthetic Judging − 1 hour • Phase 14: A Day at the Races − 1 hour (races for all classes = 1 day) • Phase 15: Data Collection − 1 hour • Phase 16: Final Submission − 1 hour Total: 32 hours

Progression: Design to Performance

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Phase 1: Zoon Air Car and Preliminary Activities

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Note: In addition to Zoon Air Car, I recommend two other tried-andtested collections of activities that are germane to the discrete science and mathematics addressed in The Science of Speed: • NASA Activities: For a good repository of activities, see Rockets: A Teacher’s Guide with Activities in Science, Mathematics, and Technology. NASA, Washington, DC: 1996 (K-12, Public Domain document EG1996-09-108-HQ). • Mousetrap Vehicles: Teacher and student materials are available from Pitsco (visit www.shop-pitsco.com).

Zoon Air Car

The Zoon Air Car materials and instructions are part of The Science of Speed curriculum. This activity affords you and the students the following benefits: • Low-cost activity that addresses principles consonant with those addressed in the CO2 investigation: motions and forces, transfer of energy, and so forth. • Use of tools to fabricate a working model. • Hands-on activity that requires students to follow instructions. If this is one of the first activities for you with the class, you will have the opportunity to observe skills, including the ability to work well alongside other students in an informal setting.

11 •

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Informal interaction with students to elicit their understanding of, among other things, nomenclature: wheelbase, axle, energy, and so forth. • Experience with performance and modifications based on performance. In measurable ways, the content and the structure of the Zoon Air Car activity resembles the larger CO2 investigation. The Zoon Air Car is a good ramp up.

Figure 1: Zoon Air Car.

Note: Construct a Zoon Air Car before you introduce the activity to the students. Construction will provide the class with a model and will provide you the opportunity to prepare for the known and unknown.

The Science of Speed poster CO2 cars from previous years/classes (without divulging information, such as speed)

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Display Class Materials

Preparation Prepare the following materials for distribution: • Student folder • “Checklist” • Zoon Air Car instructions • Zoon Air Car parts card and components

Materials List Secure the following items, which are necessary for the students to construct their Zoon Air Cars:

Required Materials: ! Scissors (ideally, one per student) ! White glue and/or cool-melt glue guns with glue slugs ! Pliers (ideally, one per two students) ! Masking tape

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Recommended Materials: ! White boards; ideally 2 feet x 4 feet, one per 3-4 students. Suggestion: Have a lumber store rip a 4' x 8' sheet into four pieces. For a class of 30, you will need two sheets (4' x 8') ripped. This will yield eight white boards (each 2' x 4'). Students will use these boards to present their ideas.

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The Science of Speed Trailer Video

View this video segment with students. This brief snapshot answers a litany of questions regarding “What are we going to do?” It is hoped that the video will grab students’ attention. The trailer will be most helpful to students who are unfamiliar with CO2 dragsters.

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Student portfolio Zoon Air Car instructions Zoon Air Car parts card and components “Checklist”

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Distribute

Students will need pencils and erasers and should write their names on the folders. Provide specific instruction referencing where the folders will be kept.

Construct Zoon Air Car

Instruct the students to construct the Zoon Air Car while carefully following the written instructions.

Query the Class When the students have completed the Zoon Air Car, it will become apparent that some cars need major work while others travel well. At this juncture, arrange the students in groups of 3-4. Be judicious: do not place three nonfunctioning cars in the same group. If you lack sufficient successes, assist the students until you have the necessary critical mass of cars that move. Students should work in small groups. Ask them: “Why do some cars move better or farther?”

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Instruct them to share among themselves in the small groups and make specific observations on the group’s white board. Encourage them to draw if the diagram helps the explanation. Note: Some cars will go backward! Others will move very quickly. Observations will vary. Tease out students’ understanding. Allow approximately 15 minutes for group work and three minutes for each group to present its observations; assign a student from each group to communicate the work. Highlight terms that are likely to reappear later because students might lack the understanding of formal terms at this point. Write these terms on a “Do Not Erase” area that is common to the entire class. This is the first occasion to formally elicit student understanding. There are four goals for this elicitation: 1. Assess student understanding of the discrete issues such as energy and friction. 2. Assemble a list of student terms, for example, “rolls better,” “rolls smoother.” Eventually, as a group, you will develop formalisms, a nomenclature that can be used in conversation and writing (see Phase 10, Propose Technical Changes). 3. Determine individual student ability. This will assist you in the management of future tasks and assignments. 4. Work in a small group and verbalize findings to the class via a white board.

Provide at least one class period after the elicitation so that students have sufficient time to modify their cars. Provide time for students to demonstrate and report on the results of the modifications. Some students will work diligently on the Zoon Air Car outside of the class period and can be afforded the opportunity to change a variable, for example, double the rubber bands or use a rubber lubricant, to improve performance. On the other hand, if you permit students to remove their work from their portfolios, the work might not return with the student.

Instruction

1. Use the material elicited from the students to frame your instruction. 2. If you are using The Science of Speed as an investigation to support physical science instruction, frame The Zoon Air Car (and CO2 car) activities. 3. Motions and Forces. Review Newton’s first law of motion, which is: a body at rest will remain at rest and a body in motion will remain in motion unless acted upon by an outside force.

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Earlier, you discussed with students the reasons why the Zoon Air Car has difficulty moving well. Students will offer terms like wobbling, rubbing against the axle, propeller hitting the support, and so forth. Some students may offer the term “friction.” If not, introduce the term. Friction is a resisting force that occurs between two materials and affects the motion of the car. Some friction is inevitable such as when wheels meet the floor or table. Most of the friction is unwanted and slows the Zoon Air Car. Ask the students to identify the areas of friction on the Zoon Air Car and how this friction can be reduced. 4. Query the students: “If every Zoon Air Car were given the same energy (turns of the rubber band), how could you improve the performance?” List the student suggestions, which might include using lubricants. If not, ask them how to improve the performance of a skateboard, a bicycle, or roller blades. If you have not used rubber lubricant with the Zoon Air Car, use one of the better cars to demonstrate the benefits of this enhancement. Instruct one of the students to wind the rubber band a specified number of times and release the propeller. Measure the distance traveled. Now apply a rubber lubricant. Repeat the test. Newton believed that an object would keep doing what it was doing until a force changed it. So, if the car is sitting on the table, it will sit there until a force compels/makes it do something else. OK. But Newton said that if it was moving, it would keep moving until another force acted on it. Well, the car stops, even if it is well lubricated! What force or forces are acting on it? 5. Transfer of energy: What propels the Zoon Air Car? Query the students and use the elicited understanding to instruct the students on potential energy (PE) and kinetic energy (KE). The twisted rubber band has “stored” or potential energy − energy waiting and ready to be used/transferred. When the propeller is released, the PE becomes KE, or movement. The rubber band turns the propeller!

Extended Activities

Students in one class may want to compare their work with that of students in another class. Students could create a chart on the board comparing distance. Encourage them to present their data in any way possible such as tables or graphs. This will afford you the opportunity to observe their abilities to collect, represent, and analyze data. These skills will be formally introduced in Phases 8 and 9. You might include a Zoon Air Car event at A Day at the Races (Phase 14)! Keep student work for future viewing including next year, open houses, and conferences.

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Phase 2: Design − Graphics and Layout

Prepare the following materials for distribution: • Grid paper (11" x 17") • “Design Rules & Specifications” • “4-View Design” • “Thumbnail Drawing Sheet” • “Design Sketch Sheet” • “Design Phase Data Sheet” • Wood blank

Preparation

Optional

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Students will also need pencils and erasers. Instruct the students to place the documents they receive throughout this activity in their portfolios. Note: If you have purchased the Pitsco DragPak (PowerPak), collect all the CO2 cartridges. The students will not need the smaller, easy-to-lose items such as washers, screw eyes, and so forth until later in the assembly process. You will need to arrange a secure place to store the wood blanks and any other collected items. If you choose not to collect the items, instruct each student to inventory his or her parts. Recommendation: If this is your first experience with CO2 cars, distribute materials only as they are required.

Encourage students to bring photos of cars including concept cars and racecars. These can be obtained from Web sites, magazines, car dealers, and so forth. Litter the room with photos and ideas. Pillage the media center, teacher lounge, and other such places for unused and outdated magazines. These images and photos will stimulate imagination and dialogue.

View With the class, view The Science of Speed video, Phases 2 and 3, Design and Design Phase − Go/No Go. Additional video support materials: Dr. Zoon Dragster Design video and Top Speed, a 4-video set (available from Pitsco, www.shop-pitsco.com).

16 Note: The five Dr. Zoon dragster videos are in the GS Package. They can be purchased as a set or individually from Pitsco. Each video lasts approximately 20 minutes and provides detailed directions for various phases of dragster design and construction.

Overview

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Use The Science of Speed poster that you have on display to walk the students through the progression, and have them follow along using their “Checklist.” Draw attention to the go/no go phases. The investigation is punctuated by reiterative “Go/No Go” assessments. These will afford you and the students the opportunity to move as a group from one phase of the investigation to the next. Lead the entire class into each phase. For example, set a date for completion of the designs so that most or all of the students are “Go” to begin Phase 4: Car Construction. Perhaps you could explain that if a car is not ready for the Trial Phase, the car will not race. Otherwise, you will be setting up the equipment often − not a slight task! Mark a class calendar and provide the specific dates when a phase must be completed. It may be difficult to keep to the calendar dates of progress/events if you are new to this investigation; therefore, you may need to amend the class schedule as you go along. If you do so, apprise students of changes! If students use planners, this would be an opportune time to record when work must be completed.

Thumbnails

It’s time to begin developing ideas! Distribute the “Thumbnail Drawing Sheets.” Thumbnails are small sketches of concepts and ideas, quickly rendered and drawn. Details are not important. Encourage the students to draw different concepts and as many as possible. The “Thumbnail Drawing Sheets” include 15 grids for sketches. Student should review photos of cars to generate ideas.

Design Sketch Distribute the “Design Sketch Sheet” and the “4-View Design Sheet.” Instruct the students to select one of the thumbnail sketches and draw a larger scale with details. The “4-View Design Sheet” includes four views: top profile, side profile, front profile, and rear profile. Instruct the students to draw top and side profiles. If they are inclined, they may draw the other views: front and rear. They should include profile lines.

Scale Design Distribute:

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Grid paper (11" x 17") “Design Rules & Specifications” “4-View Design” “Design Phase Data Sheet” Go/No Go gauges Wooden body blanks

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The “Design Phase Data Sheet” includes the commonly referenced measurements. If you purchase materials from Pitsco, the majority of the measurements (and ranges) on the “Design Phase Data Sheet” will be sufficient for design. For an exhaustive list, students should refer to the “Design Rules & Specifications.” A third tool for measurements of acceptable ranges is the Go/No Go gauge. The gauge is the easiest tool for measuring acceptable ranges. Note: The “4-View Design Sheet” will prove most helpful as you informally instruct students. Instruct the students to use a permanent marker to write their names on the bottom of the wooden body blanks. Next, instruct them to trace the side view and top view of the wooden body blank and align the front and rear with profile lines. Collect the body blanks after students have written their names on the bottom and store them. You will redistribute them in Phase 4: Car Construction. The measurements listed on the “Design Phase Data Sheet” should appear on the design drawing using standard drawing procedures such as line arrows. This measurement labeling will make assessment of the design much easier.

Figure 2: Sample design drawing.

Notes: 1. The bottom of the car blank forms a right angle with either end. The longest length is the top. This is very important; otherwise the CO2 cartridge will not be parallel to the track surface. Among other problems, the launch pin will not strike the cartridge squarely.

Figure 3: 90-degree angle.

2. Encourage students to draw the locations of the screw eyes close to the axle locations on their design, though not directly under the axle because the screw eyes must be screwed into the wood and could penetrate the axle hole area. Locating the screw eyes in the vicinity of the axles will improve stability.

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Phase 3: Design Phase â&#x20AC;&#x201C; Go/No Go

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Instruct the students to complete data entry onto the â&#x20AC;&#x153;Design Phase Data Sheet.â&#x20AC;? Carefully check the designs in special reference to the design rules and specifications. The designs should receive your signature, provided they are acceptable and within the specified ranges of measurements. Instruct students to place all documents into their portfolio. Note: In the next phase, Car Construction, students will shape a prototype from polystyrene (optional) and construct a car from basswood or balsa wood. You need to decide how the designs will be transferred to the polystyrene and wood. Two choices are common: 1. Students cut the design from a photocopy of the final design on grid paper and trace the design onto the polystyrene. In turn, the students tape the design views (top and side) onto the wood and cut the wood, following the design. If you select this option, you must photocopy the designs to scale so that the originals can be kept in the portfolios. 2. Referring to the final design on grid paper, students measure and draw on the polystyrene and wood. Students do not cut out the designs. This option is strongly recommended for two reasons: first, the original drawing is preserved, which is particularly important if students advance to race events that require drawings; second, students reinforce their skill of measuring accurately.

Extended Activities

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The following activities will reinforce designing and critiquing of designs. 1. Top 10 Reasons for Design Flaws For this activity, you need cars that have been designed and cut (not necessarily painted) but violate at least one of the design rules and specifications. This will not be possible for teachers who are new to the CO2 investigation. Take eight cars that violate obvious and not-so-obvious design rules. Number the cars 1-8 with a permanent marker. Create a quiz sheet and ask students to find the 10 rules violations in the eight cars. The students should use the “Design Rules & Specifications” sheet while evaluating the eight cars. With more violations than cars, students must determine which cars have more than one violation. Instruct them to identify which rules have been violated by which cars. To make the task slightly more difficult, have 10 violations in seven of the eight cars. This means one of the cars is acceptable. If you do this, simply state: “There are 10 violations in this group of eight cars.” Note: Later in this guide, a reminder will be given to keep “mistakes.” These cars will be the design flaw quiz cars for future classes. 2. Simulation Software Car Builder software and Dragster Designer software, available from Pitsco, are excellent tools; they reinforce the design and testing phases. Students should be afforded the opportunity to use the software throughout the investigation, beginning with this phase. Students should place printed results in their portfolios.

________________________________________________ Enter the next phase as a group. All students should have an acceptable design. ________________________________________________

Phase 4: Car Construction − from Design to Model In this phase, students use a variety of tools to construct a wooden car based on their design. They should not finish the cars, in other words, not finely sand, prime, or paint. Rather, students should get a general idea of the shape and dimension and test their design. Thereafter, the students should compare all their test results and make design modifications. Students should not finish the car to the point that modifications are not possible.

Preparation Prepare the following materials for distribution: • Polystyrene body blank Note: If you purchased the Getting Started Package, you do not have polystyrene body blanks. Therefore, if you want to engage the students in the prototype activity, you will need to purchase the polystyrene body blanks separately. • Wheels, axles, straws, and washers • Sandpaper

Materials List

In addition to the student materials in the portfolio, secure the following: • Scissors (ideally, one pair per student) • Wire snips or hacksaw (one is adequate for cutting axles) • Transparent tape (only necessary if students cut and tape the design) • Scales (triple beam or electronic) • Safety goggles • Resealable bag (sandwich-size), one per student

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Students will also need pencils and erasers. Note: Safety is an important consideration throughout the investigation, particularly when students are using tools. Most teachers have safety procedure tests for their labs. Similar tests for the use of your equipment should be required. For general safety observations, see Dr. Zoon Dragster Production: Power Tools video. Moreover, many states have laws, such as the Minnesota Eye Protective Devices Legislation (126.20). Know your equipment, the students, and applicable laws.

Optional

Students need a storage container for the body blanks, parts, and so forth. If you ordered individual kits, each student receives an ideal box. Otherwise, boxes are available from Pitsco or a labeled shoebox is a good solution. A plastic shoebox (Rubbermaid or other manufacturer) is an inexpensive option at approximately $1.

Tools and Wood Materials Your choice of wood type determines the requisite tools. Experience is the best teacher. Begin by building one car from each of the materials. Your experience will guide your decision of wood types for your students. Briefly, here are the advantages and disadvantages of each wood type. Basswood − Advantages • Final car is stronger, better able to withstand dropping and crashing.

21 • • • •

Wood surface is not porous and is easily finished. Less chance of having an underweight car, which is less than 45 grams. More durable; car is more likely to hold up for multiple races. More forgiving to work with; more difficult to make fatal cuts.

Basswood − Disadvantages • Harder wood is more difficult to shape. • More construction time is required. • More tools are required; power tools highly recommended. • Final car design is denser and therefore slower (depending on design).

Balsa − Advantages • Softer wood is easier to work with and less dense. • Less construction time is required. • Fewer tools are needed; hand tools could be adequate. • Final car is less dense and therefore faster (depending on design).

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Balsa − Disadvantages • Final car is more fragile and subject to breaking. • Wood is porous and requires primer and sanding for an excellent finish. • Wood scratches and dents easily before the car is painted and or lacquered. • Better chance of having an underweight car, which is less than 45 grams. • Less durable; car is not as likely to hold up for multiple races. • More likely to ruin car by careless cutting and/or sanding.

Essential Tools: Balsa

Foam cutter − necessary if the students construct a polystyrene prototype. Drills − nonelectrical hand drills are adequate; an electric drill is preferable. Neither is as accurate as the drill press on which the body blank is placed on the drill bed and the hole is perpendicular to the drill bed. If nonelectrical hand drills are used, you need approximately one per five students, whereas one drill press is adequate for a class. A drill press is highly recommended. 3/16-inch drill bit − one per drill and extras in the event of loss or breakage. Coping saws − minimally, one per four students.

• •

22 •

•

Sandpaper − many of the Pitsco kits include sanding paper. Coarse (80 grit), medium (120 grit), and fine (220 grit) sheets should be cut into 3-inch x 3-inch squares. Sanding sponges of various grit values − the typical sponge is 5" x 3" and can be cut into five pieces (each 1" x 3").

Essential Tools: Basswood •

•

Tool List (Ideal)

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•

Foam cutter − necessary if the students construct a polystyrene prototype. Drill − a hand-powered drill is adequate, but a drill press is preferable; see previous explanation. Auger sanding adapters are valuable for drill presses and are effective for sanding/contouring the same way a Dremel tool does. If drilling axle holes is the only purpose for the drill, one drill is adequate. A drill press is highly recommended. 3/16-inch drill bit − one per drill and extras in the event of loss or breakage. Scrolls saws and/or band saws − the more, the better. Sandpaper − many of the Pitsco kits include some sanding paper. Coarse (80 grit), medium (120 grit), and fine (220 grit) sheets should be cut into 3-inch x 3-inch squares. Sanding sponges of various grit values − the typical sponge is 5" x 3" and can be cut into five pieces (each 1" x 3").

This list maximizes tools and time. If the students are using balsa, tooling time is shorter. • Foam cutter − necessary if the students construct a polystyrene prototype. Accumulate these over the years. They can be used for all modeling and prototyping projects. • Drill press with auger sanding adapters − the drill press can be used for drilling axle holes and sanding. • 3/16-inch drill bit − store extra 3/16-inch bits. • Four scroll saws and/or band saws. • Four belt, disk, and/or oscillating sanders. • 10 Dremel or handheld power sanders with accessories. • Variety of wood files and rasps. • Emery boards. • Sandpaper − many of the Pitsco kits include some sanding paper. Coarse (80 grit), medium (120 grit), and fine (220 grit) sheets should be cut into 3-inch x 3-inch squares.

View With the class, view The Science of Speed video, Phase 4: Car Construction. Additional support materials: Dr. Zoon Dragster Production: Hand Tools video, Dr. Zoon Dragster Production: Power Tools video, and Top Speed, four-video set available from Pitsco.

Redistribute

•

Body blanks (students’ names should be on the bottom) Final design drawings on grid paper (If the students are cutting out the designs and/or taping them to the polystyrene and /or wood, you need to distribute properly scaled photocopies of the designs.) Approved “Design Phase Data Sheets” (if you collected these previously) Final scale drawings on grid paper and photocopies if these are to be cut out Polystyrene body blank for the prototype

• •

Note: The Getting Started Package does not include polystyrene body blanks. Therefore, if you are using this package and want to engage the students in the prototype activity, purchase the polystyrene body blanks separately.

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Prototype

Students should either cut and trace the designs or measure and draw them onto the polystyrene. They should begin with the side view; cut and trace or draw. Using the foam cutter, cut the side shape. In turn, cut and trace or transfer the top design. It is much easier if the side cutaway is reattached before the top view is drawn and cut. Instruct the students to place their names on the prototypes.

Figure 4: Polystyrene cut into pieces.

The polystyrene prototypes afford the students the opportunity to follow the same cutting process that is used in the subsequent construction with wood. Second, they have a good idea of the three-dimensional shape. Third, the prototypes are a great visual cue in the process from design to testing. Display the prototypes along with the car and portfolio materials at all open houses and similar events. Note: It is most helpful if you allow students to practice cutting with the wire foam cutter. Save pieces of polystyrene for this purpose. Second, it is very constructive to have the process on display: 1. side and top views drawn, 2. side view cut, and 3. side pieces reattached with tape. This procedure is demonstrated in the Dr. Zoon video materials.

Construction

Redistribute

â&#x20AC;˘ Body blanks (student name should be on the bottom)

Transferring the Design to the Body Blank

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As with the polystyrene body blanks, students should cut, tape, and trace the designs or transfer them, measuring and drawing onto the wood. Here is the procedure for the cut-tape-and-trace option: 1. Cut out the side and top views from the photocopy of the final scale design drawing on grid paper. 2. Take the side view and tape it to the side of the blank. Be sure the bottom and short side are 90 degrees apart. 3. Trace the side view with a pen or pencil. 4. Push the pen or pencil through the side view design at the two axle hole locations. 5. Remove the side view design. 6. Tape the top view to the top. 7. Trace the top view with a pen or pencil. 8. Remove the top view design. Here are the directions for the transfer method: 1. Using the original final scale design drawing, carefully measure and transfer the side and top views. Transfer front and rear views if you drew them (optional). 2. Mark the front and rear axle locations. Regardless of the chosen method of transferring the design from the grid paper to the wooden body blank, the subsequent steps are the same for all students.

Drilling the Axle Holes First, and most importantly, drill the axle holes before cutting the side and top views. Imagine trying to hold the car in your hand or on the drill press bed if the rough contours were cut! Impossible. Axle holes must be perpendicular to the body length or the car will drift left or right, depending on the angle of the axle in relation to the body.

Cutting the Wood

Students should begin with the side view. After the side cut is made, students should reattach the pieces with tape before the top view is cut. In other words, reassemble the body blank, and then cut out the top view.

Sanding/Contouring

The tendency is to sand aggressively, even when using Dremel tools, and rush toward finishing the car. Encourage students to avoid this. Rounding edges and so forth is fine. If students make hasty commitments, subsequent changes based on the test data will not be possible. The test data will be irrelevant and performance will be less than what is possible if the test data were considered seriously.

Inevitable Mistakes Along the Way

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Regardless how carefully students build or how many years you have been building, testing, and racing CO2 cars, mistakes will happen. It is hoped that none of the errors requires medical attention. The lesser errors can be equally mortifying: students have been heard weeping and screaming when an errant saw blade invades areas of a car body rendering the car unworthy of racing. Be prepared because this will happen − often − especially in your early experiences. Of course students’ mistakes will slow the pace for others who seem to lean in the direction of “hasty.“ The further along in the process, the more devastating the results tend to be. Your response to these unwanted mistakes is critical. Assuming students have not been careless or indifferent, be supportive. On the positive side, you can use their mistakes for the Phase 3, “Top 10 Reasons for Design Flaws” extended activity. Depending on how many of these you encounter, trade the quiz sample for a new body blank. And, as much as possible, lend a word of encouragement and work with the students to get them up to speed. Note: If this practice becomes excessive, you may need to charge a minimal amount for a new body blank.

Pretrial Assembly Distribute • • •

Wheels, axles, straws, washers, and screw eyes Resealable bag (sandwich-size), one per student Storage box (optional)

These materials may be shipped in bulk or sorted for each student depending on what materials were ordered. In any case, care should be taken so that parts are not lost or misplaced. Each student should use a permanent marker to label the bag and car. Note: Do not distribute cartridges.

Assembly Procedures

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1. Cut straws to fit the front and rear axle holes. The lengths should be the same as the body width at the front and rear axles. 2. Slide the straws, or axle bearings, into the axle holes. 3. Insert axles into front and rear axle holes. 4. Insert one washer and wheel on each axle end. 5. Assist the students with the screw eyes. If the students are using balsa wood, be very careful. The wood is fragile. Screw eyes should be centered across the width of the car. Students should be cautious and avoid inserting the screw eyes into the axle areas. Notes: • If you do not intend to use the wind tunnel in the next phase, you do not need to install the screw eyes until the trial races. • Student may request a tool with which to shorten the axles. Either cut the marked distance for them or demonstrate and, with safety goggles on, allow them to cut their axles.

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Phase 5: Collect Data − Meaningful Measurements In this phase, students use a variety of devices to measure their models. There are four additional fields in the “Trial Phase Data Sheet”: mass, drag, front lift, and rear lift. If you do not have access to a wind tunnel, the last three are moot.

Preparation Prepare the following materials for distribution: • “Trial Phase Data Sheet”

Equipment List

In addition to the student materials in the portfolio, secure the following: • Scales (triple beam and/or digital) • Wind tunnel (several types available from Pitsco) • Smoke visualization tunnel (available from Pitsco) • Roll test ramp (available from Pitsco)

View

With the class, view The Science of Speed video, Phases 5 and 6, Data Collection and Trial Phase – Go/No Go. Additional video support materials: Dr. Zoon Dragster Testing video.

Activities

• “Trial Phase Data Sheet”

Distribute

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This phase includes up to six activities: 1. Enter the known data on the “Trial Phase Data Sheet.” The tendency is for students to copy the data from the “Design Phase Data Sheet.” Discourage this because the design drawing and the actual car as it is cut may differ. It is hoped that any discrepancies are not significant and the measurements are still within acceptable ranges. 2. Determine the mass of each car, including all parts except the cartridge. 3. Ramp test. A simple ramp on which to roll the car affords a visual indicator of stability and the car’s ability to travel straight. Any tendencies become obvious. If a ramp is unavailable, a good center push from the rear on a flat surface should be used. 4. Visualize the aerodynamic flow lines of the cars by using a flow visualization tunnel. This unique equipment provides visual indicators that are, in part, measured by the wind tunnel. 5. Measure drag and lift. Acquiring this data requires a wind tunnel. 6. Peer assessment. This is the first instance when the peer assessment pedagogy is used in this investigation. It is important that students are very careful, attentive, and critical (in a positive way) as they check the data recorded by the designer. Peer assessment should be done after all the data is reported on the “Trial Phase Data Sheet.” The peer student must print and sign his or her name on the data sheet.

Managing the Activities

Three mitigating factors determine how you manage the five data collection activities. First, how many of the five activities do you expect to include? The fewer, the easier. For example, if you do not plan to use the wind tunnel data, your management is easier. Conversely, the wind tunnel data is very important! The second factor is the maturity of your students. Only you know how capable they are of independent data collection. You will not be able to manage all the activities. The third factor is a combination of your familiarity with the equipment and your ability to keep all the balls in the air. If you have access to the equipment, perhaps you could train students as lab assistants. In subsequent years, you should have students who have matriculated to the next grade who would be thrilled to share their experience and knowledge.

Extended Activities

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The extended activities mentioned earlier are appropriately repeated here as an effort to reinforce the skills of constructing and testing: 1. Top 10 Reasons for Design Flaws For this activity, you need cars that have been designed and cut (not necessarily painted) but violate at least one of the design rules and specifications. This is not possible for teachers who are new to the CO2 investigation. Take eight cars that violate the obvious and not-so-obvious design rules. Number the cars 1-8 with a permanent marker. Create a quiz sheet and ask students to find the 10 rule violations in the eight cars. The students should use the “Design Rules & Specifications” sheet while evaluating the eight cars. With more violations than cars, students must determine which cars have more than one violation. Instruct them to identify which rules have been violated by which cars. To make the task slightly more difficult, have 10 violations in seven of the eight cars. This means one of the cars is acceptable. If you do this, simple state: “There are 10 violations in this group of eight cars.” 2. Simulation Software Car Builder software and Dragster Designer software, available from Pitsco, are excellent tools; they reinforce the design and testing phases. Students should be afforded the opportunity to use the software throughout the investigation. Students should place printed results in their portfolios.

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Phase 6: Trial Phase – Go/No Go

Instruct the students to submit the “Trial Phase Data Sheet.” Each sheet should include the name and signature of another student. In turn, the sheet should receive your signature, provided the designs and data are acceptable and within the specified ranges of measurements. Collect the cars and the “Trial Phase Data Sheet.” Check for two items: • Glaring anomalies such as measurements on the data sheet that clearly do not correspond to the car. • Ensure that the screw eyes are aligned.

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________________________________________________ Enter the next phase as a group. All students should have a race-worthy car. ________________________________________________

Phase 7: Trial Races − Performance

The trial race is not a head-to-head competition. This is an opportunity to collect data. Therefore, do not run two lanes simultaneously. Instead, focus on the procedure of racing and collecting the times.

Preparation

Prepare the following materials: • One lane for racing, including a launch pod, monofilament line, and a method for stopping the cars. If your system allows you to set up two lanes, one at a time, this setup will save you the time of threading the screw eyes onto the monofilament line. If you are racing on a floor, make sure the surface is clean and car friendly with no opening doors, cracks in the floor, and so forth. Test the setup. Note: Thoroughly read the directions of your system. A variety of solutions are available from Pitsco. Test the system and have plans for failed equipment. • Sufficient CO2 cartridges for the trial races.

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Timing device − the Pitsco devices are accurate to 1/1000th of a second. If you must use a manual device, be sure that the same person is operating the device and that it is as accurate as possible. “Race Time Sheet” for each class. Cars − confirm that they have screw eyes, include the students’ names, and are race worthy.

View With the class, view The Science of Speed video, Phase 7: Trial Races.

Race and Record Times

If possible, solicit the assistance of a colleague. There is plenty to manage: starts, finishes, prepping cars (inserting CO2 cartridges), managing heightened energies, and so forth. Each student should record his or her own time. Be sure to record the times on the “Race Time Sheet.”

Collect All Cars

Do not return a car to a student until all students have completed the three subsequent phases of the investigation: data collection, data analysis, and proposed technical changes. If you return the cars, the students will be tempted to begin making changes or simply finish/paint their cars.

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Phase 8: Collect Data – Mathematical Information

This phase and the following phase, Data Analysis, are principally concerned with mathematical information gathered from the trial races. Therefore, this is an opportune time to work with a colleague in mathematics. In addition to gathering and sorting information, students are required to select data to represent graphically and they are called upon to interpret the data for meaning.

Preparation Prepare the following materials for distribution: • “Posttrial Phase Data Sheet” Prepare the following materials for redistribution: • “Trial Phase Data Sheet”

View With the class, view The Science of Speed video, Phase 8: Data Collection.

Distribute • •

“Posttrial Phase Data Sheet” “Trial Phase Data Sheet”

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Students should transfer the data from the “Trial Phase Data Sheet” to the “Posttrial Phase Data Sheet.” Instruct the students that there are two new fields on the “Posttrial Phase Data Sheet”: Trial Time (seconds) and Trial Speed (mph). The trial time is self-explanatory and was obtained at the trial races. The trial speed must be calculated. The following two considerations will determine whether you assign this task to the students: 1. Mathematical ability and exposure to the discrete concepts of distance, rate, and time. 2. Time for the task at hand (conversations, graphing, and so forth). In any case, you have three options: 1. Provide conversions for the students. In fact you could create a conversion table that is based on the fixed distance of the track. 2. Provide the formula with a modicum of explanation. Students would then plug in the variable (time in seconds) and calculate. 3. Provide the necessary instruction so that all students are capable of calculating speed in miles per hour.

In any case, all students should have a point of reference; they saw how fast the cars moved. Is that faster than a runner? A bicycle? A car in the neighborhood? A pitched baseball? Above all, pace the investigation while remembering that students will graph data and make proposals for technical changes before finishing their cars! Consider several factors: how much time you have until the investigation must be completed, the level of student interest in the mathematics and writing, and the ability of the students to manage the tasks.

How Fast is Fast: The Mathematics of CO2 Speed Discuss the difference between average velocity or speed and instantaneous velocity or speed. For example, if a student ran from one end of the soccer field to the opposite end, he or she could sprint, jog, and then sprint to the finish. The average speed would be the distance covered divided by the time, but the speed at any given time would vary greatly. The instantaneous velocity would be the speed at a particular point in time, such as at the 30-yard line when the student was sprinting.

The same is true for the CO2 car: there are times the car is traveling slower and times when it is traveling faster. In this investigation, we are interested only in average speed. So we would like to calculate the rate (speed) of travel. Rate = distance/time. For example, if you drove from Minneapolis to Chicago − 420 miles − and the drive took 7 hours, what would be the average speed of the trip? Average Speed = Distance/Time Average Speed = 420 miles/7 hours Average Speed = 60 miles/hour In a CO2-dragster race, the distance is in feet and time is measured in seconds, so a few conversions are necessary: Average Speed = Distance/Time Distance = 65 feet, 7.5 inches or 65.625 feet Average Speed = [(65.625/time) x 3,600]/5,280 Note: We need to determine feet per hour [(65.625/time) x 3,600] (3,600 is the number of seconds in one hour) and then convert feet into miles per hour (5,280 is the number of feet in a mile). Example: 1.7-second race Average Speed = [(65.625/1.7) x 3,600]/5,280 Average Speed = 26.32 mph

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Collect the “Posttrial Phase Data Sheets” from the students.

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Phase 9: Analyze Data − Interpretation

The purpose of this phase is to provide students with sufficient meaningful data so that they are able to make decisions based on good evidence. Effectively, they will attempt to answer the question: “What are the common characteristics of the faster cars?” Along the way, students will continue to make decisions based on speed and aesthetics. They will compromise, reaching a middle ground so that form and function are balanced.

Preparation Prepare for Distribution: • “Graph Data Sheets” (three per student)

33 In one form or another, the students need access to the data for the entire class. Collect all the data and enter it into a spreadsheet. If possible, solicit the help of a student. Use the information listed on the “Posttrial Phase Data Sheets.” If electronic distribution of a spreadsheet is not an option, create a legible table. In either case, reproduce the information for each student.

Class 1 Car Data Student Name

Car Name

Car Length

Wheelbase

Time

...

Sprint King 255 mm

170 mm

1.88

...

Sally Jones

Bulldog

280 mm

150 mm

1.77

...

Teresa King

Zoomer

220 mm

1.94

...

Jim Strong

Lightning

290 mm

160 mm

1.80

...

Chuck Banks

Galaxy I

280 mm

260 mm

1.93

...

Erin Farmer

Hooper

233 mm

130 mm

1.71

...

John Smith

Figure 5: Sample partial table.

Recommended Materials

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White boards: 2' x 4', one per 3-4 students (same as used in Phase 1).

View

With the class, view The Science of Speed video, Phase 9: Data Analysis.

Instruction

Earlier, during the Zoon Air Car preliminary activity, you introduced motions and forces. With the class revisit the conclusions reached previously about how to reduce friction and thereby improve performance.

Query the Class

Students should be in small groups. Ask them, “Why do some cars move faster than others?” Instruct them to share among themselves in groups of three or four and generate a few ideas. Encourage them to draw their ideas, for example, an illustration of air hitting the front of the car. As students present their work on the white boards, tease out their understanding. Undoubtedly, they will begin to use words that can be formalized: resistance, friction, and so forth. As in the earlier group presentations, write those words on a “Do Not Erase” area that is common to the class. For example, write these definitions:

34 •

Surface friction is friction between parts. Sometimes this slows the car. How can this be reduced? Some surface friction is necessary, such as the tires meeting the race surface (floor or track). This is often called traction. • Fluid friction is the air resistance on the car, which increases when the car moves faster! Fluid friction is observed in the visualization tunnel and measured in the wind tunnel. This type of friction can be reduced through contouring, sanding, and so forth. Now assign each group the task of graphing on the white board a relationship to determine what characteristics affect time/speed. Assign examples such as drag and mass as well as non-examples such as body width (rear axle), though there may be an indirect correlation! Agree which axis on the graph you will use for speed. Provide each student with the data you generated. Depending on the students’ ability, you will need to get them started. When the graphs are complete, each group should present its results. In the end, have them answer the questions: “Is there a correlation between speed and your variable, such as mass? If so, what is the relationship?”

Distribute

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• “Graph Data Sheets” (three per student) Allow the students time to work independently and graph two examples of a relationship between a variable and speed. The students may select any two examples, provided there is a correlation. Note: If you have entered the data electronically, generating graphs is simple. However, keep in mind that this is a good opportunity for students to graph their data and, later, interpret it for meaning. Informally observe students’ work and interact with them. Encourage students to make a third graph or generate a formula for a relationship. They might see linear and/or nonlinear relationships. To be sure, because of multiple variables, the graphs will not be “clean” with perfectly straight lines. Nonetheless, the data is real to the students.

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Phase 10: Propose Technical Changes – Technical Writing

Ideally, the task of writing will involve the language arts teacher and English as a Second Language (ESL) or English Language Learners (ELL) teachers, assuming you have students for whom English is not their first language. The main advantage of using word processing software is that editing is much easier. Whether you require revisions and how you will assess the writing is your determination. The assessment rubric in Appendix B is general and adequate, though you may want to develop it for your situation and emphasis.

Preparation

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Recommended Materials

Prepare the following materials for distribution: • “Technical Changes Sheet”

White boards: 2' x 4', one per 3-4 students.

View

Distribute

With the class, view The Science of Speed video, Phase 10: Propose Technical Changes.

• “Technical Changes Sheet” The five-paragraph essay that students write should be in the standard format used for most writing assessments. Proposals for technical changes should be based on good evidence shown in the class data and the student graphs. It is hoped that the growing list of terms and expressions will find their way into the students’ writing. Once again, students will make decisions based on two sometimes mutually exclusive issues: speed and aesthetics. Collect and assess the proposals for technical changes.

Instruction Earlier, during the Zoon Air Car activity, you introduced transfer of energy. With the class revisit the conclusions you reached about the energy transfer in the Zoon Air Car.

Query the Class

Students should be in small groups. Ask them, “What energy moves the CO2 car?” Instruct students to share among themselves, in groups of three or four, and generate a few ideas. Encourage them to draw their ideas. As students present their work on the white boards, tease out their understanding. As in the earlier group presentations, write any words (including formalisms) and ideas on a "Do Not Erase" area that is common to the class. The common misconception of middle-level students is that the escaping gas pushes the car. A demonstration will help explain what happens. First, review Newton’s third law, which is that for every action there is always an opposite and equal reaction.

Demonstration

Materials needed: • 1 balloon (cylindrical, like the shape of the CO2 cartridge) • 4 inches of masking tape • 1 straw • 20 feet of monofilament line • 1 paper clip

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Inflate the balloon and tape the straw onto the balloon lengthwise. Thread the fishing line through the straw as shown in Figure 6. Instruct two students to hold the ends of the monofilament line tautly. Query the students: “What will happen when you release the clip?”

Figure 6: Thread the fishing line through the straw.

Draw the balloon and pressure lines on the board to illustrate the action and the equal, opposite reaction.

Figure 7: How a pressurized CO2 cartridge works.

Mass of Compressed CO2

Do not apprise the students of the mass of the compressed CO2. Rather, query them if they think air has mass. Begin by weighing an inflated basketball. Deflate. Reweigh. Ask the students to estimate the mass of the compressed CO2 in the cartridge.

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Phase 11: Design Modifications & Detail − Implementation

Students will be eager to receive their cars and begin modifying and detailing (paint, clear coat, and so forth). All changes must be proposed on the “Technical Changes Sheet.” In other words, you should not see design modifications that you have not already read about! Students must note the design modifications on the original “Design Phase Data Sheet.” If the design drawings are part of the judging, care should be taken in the erasing and redrawing. These changes will be reflected in the car and, subsequently, in the “Race-Ready Phase Data Sheet” in Phase 12. Set a date when all changes are due! Otherwise, perfection will demand an eternity of modifications.

Preparation Prepare the following materials for redistribution: • “Technical Changes Sheet” and supporting “Graph Data Sheets”

38 •

CO2 cars − students will disassemble the wheels and so forth; therefore, they will need the resealable bags to hold the parts.

Tool List (Ideal) • • • • •

Scroll saws and/or band saws; only for basswood when radical changes are proposed Belt, disk, and/or oscillating sanders; only for significant modifications Dremel or other hand-held power sanders with accessories Variety of wood files and rasps Emery boards Sandpaper, especially fine grit

•

Paint Supplies

•

Primer, especially for balsa Paint Brushes Dragster paint stands (available from Pitsco) 3/4-inch dowel rod (approximately 20 inches long) − the dowel can be inserted into the cartridge hole and can be held while painting. Aerosol finish (clear coat)

Optional Supplies Decals Airbrush station

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• • • • •

Caution: The most important consideration is ventilation. Ventilation should, in large measure, determine what materials you introduce for painting and finishing. The Getting Started Package includes an excellent assortment of brushes, paints, and so forth, as well as five dragster paint stands.

Equipment List • • • •

Scales (triple beam and/or digital) Wind tunnel (available from Pitsco) Smoke visualization tunnel (available from Pitsco) Roll test ramp (available from Pitsco)

View With the class, view The Science of Speed video, Phase 11: Design Modifications & Detail. Additional video support materials include the Dr. Zoon Dragster Finishing Video.

Redistribute • •

“Technical Changes Sheet” and supporting “Graph Data Sheets” CO2 cars − students will disassemble the wheels and so forth; therefore, they will need the resealable bags to hold small parts. Ask them to remove the screw eyes; these are not needed until A Day at the Races. Moreover, the screw eyes have a tendency to rip and tear the wood, particularly balsa, when handled poorly. Students will need them for weighing the car and its parts. Instruct the students to continually check the mass of their cars if they are close to the 45-gram minimum, which includes all parts except the CO2 cartridge. Paint will add minimal mass. Paint, in fact, is the only way to add mass to a car. Students should have access to the ramp and wind and smoke visualization tunnels, if available, as they continue to measure the effects of the modifications. This is a good opportunity for students to demonstrate mastery as they reuse the equipment.

Reassembly

At the designated time and date, instruct the students to reassemble the cars and prepare for the Race-Ready Phase.

Extended Activities

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1. Simulation Software Car Builder software and Dragster Designer software. Students should place printed results from the software in their portfolios. 2. Mass of paint on a CO2 car Collect more data and create another table on the display board.

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Phase 12: Race-Ready Phase – Go/No Go Prepare the following materials for distribution: • “Race-Ready Phase Data Sheet”

View With the class, view The Science of Speed video, Phases 12 and 13, RaceReady Phase – Go/No Go and Design and Aesthetic Judging.

Distribute •

“Race-Ready Phase Data Sheet”

Students should enter data on the “Race-Ready Phase Data Sheet.” Data from the “Posttrial Phase Data Sheet” should not be transferred because all students have introduced changes, such as modifications and paint. Students should include their predictions as recorded on the “Technical Changes Sheet.” As during the trial phase, each sheet should include the name and signature of another student as part of a peer assessment. In turn, the sheet should receive your signature, provided the designs and data are acceptable and within the specified ranges of measurements. Collect the cars and the “Race-Ready Phase Data Sheets.” Check for two items: 1. Glaring anomalies such as measurements on the data sheet that clearly do not correspond to the car. 2. Ensure that the screw eyes are aligned.

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________________________________________________ Enter the next phase as a group. All students should have a race-worthy car. ________________________________________________

Phase 13: Design and Aesthetic Judging − Peer Evaluation

The following procedure is merely one of many that could be used to judge the aesthetics of the CO2 cars. This peer evaluation does not include the design drawings. Rather, the intent is to judge aesthetics. Generally, it would be advantageous to solicit the cooperation of a teacher who is teaching students who will be in your class the following year. Ideally he or she will allow the students to view and judge the cars. Prime the students for what awaits them in your class. Prepare a car name label for each car. If you entered data electronically in Phase 9, the car names have already been entered. Simply format the data and print labels. Do not put student names on the cars or the labels; otherwise, judging will become a popularity contest. Your students, the designers, should not be in the vicinity during judging; they should be in another class, at lunch, or elsewhere. It is possible to have another class of designers judge; however, word spreads quickly regarding who built which car.

Prepare an adequate viewing area while not allowing the students to handle the cars. The cars have a tendency to roll on account of the wheels! Ideally, place a tape line such as “Danger: Construction Zone” to curb the temptation to touch the cars. Explain the judging to the visiting students. Provide them a sheet with the car names alphabetically arranged. Instruct them to award points for the five cars that they like best. Five points are awarded for the car they deem to be best, four points for second best, and so forth. Remind them that five points is the highest rating. The process should take approximately 15 minutes. Check the sheets as students return them; only five cars should receive points. By allowing students to award points to five different cars, it is hoped that all cars will be awarded some aesthetic points. Share the results with the class. Either read each assessment and tally the points with the students, which is suspenseful, or tally the points separately and share the results with the class. Keep the cars for the next phase. If possible, take two photos, preferably digital, of each car. Print the photos and distribute a print to each student in Phase 16. Save the other photo of each car for your repository.

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Phase 14: A Day at the Races − Performance

This is the day, the culminating event. The primary emphasis should be performance in special reference to the design modifications and prediction in the technical writing. In other words, this is not entirely about which car is fastest, although that is a part of the experience. Above all, your goal is to affirm good work. There are several ways to accomplish this: • Acknowledge the good work of the class. Working with tools, learning new technologies, sharing information, and so forth should be applauded. • As a class, each student should sort the documents in his or her portfolio. This will be a vivid reminder of how much work has been accomplished.

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Draw attention to the “Race-Ready Phase Data Sheet” and the posttrial/prerace prediction. Indicate that the goal for each student is to design and build a car that performs as predicted. The scientific process encourages modification to accomplish that goal. Query the students: “How good is your prediction?”

Preparation

Prepare the following materials: • Two lanes for racing including launch pods, monofilament lines, and a method for stopping the cars − if you are racing on a floor, make sure the surface is clean and car friendly (no opening doors, cracks in the floor, and so forth). Test the setup. • Sufficient CO2 cartridges for the race format; see Appendix C: A Day at the Races. • Timing device − the Pitsco devices are accurate to 1/1000th of a second. • Cars − confirm that they have screw eyes, include the students’ names, and are race worthy.

View

With the class, view The Science of Speed video, Phase 14: A Day at the Races.

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Instruct students to record race times. It is highly recommended that all students receive a copy of the race brackets if used so that they can be actively involved in tracking cars and times. Keep the cars. You will return them when the portfolios are complete.

________________________________________________ Sweep up, buy the janitor a soda, and then go home! ________________________________________________

Phase 15: Collect Data Preparation Prepare the following materials for distribution: • “Final Data Sheet”

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“Final Data Sheet”

Instruct the students to enter the following data: Race Time and Aesthetic/Design Points. Use the procedure outlined in Phase 8 to calculate speed in miles per hour. While students are working, circulate and enter the aesthetic/design ranking. If you have sufficient time, create a table on the board and collect the data for each student with special reference to the difference between prediction and final performance. The smaller the range, the better the predictions. Also, you could compare the trial times to the final race times and celebrate improvement. This will be a good opportunity to discuss the event and begin to bring closure to the investigation. Solicit student feedback: â&#x20AC;&#x153;What should we keep and what should we change?â&#x20AC;? If students advance to school-wide or regional races, notify the students as soon as possible. See Appendix C for recommended criteria.

__________________________________________________________

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Phase 16: Final Submission â&#x2C6;&#x2019; Portfolio Is Complete

Instruct the students to assemble their portfolio materials. If you took a photo of each car during Phase 13, distribute the photos to the students. If you have scheduled an open house, arrange the portfolio materials for viewing. Provide summative assessment. This should not be based on how each student finished the race. Evaluate his or her portfolio. A rubric is provided in Appendix B.