Carolina STEM Challenge Balloon Race Cars carolina stem...which can be scored using the Design...

Carolina STEM Challenge®

Balloon Race CarsTEACHER’S MANUAL

AND STUDENT GUIDE

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Table of Contents

TEACHER’S MANUAL

Safety .......................................................................................... 3

Background ................................................................................ 3

Preparation ................................................................................. 4

Procedure .................................................................................... 4

Answers to Questions in the Student Guide ............................ 4

Differentiated Instruction .......................................................... 5

Extension Activities .................................................................... 5

Resources .................................................................................... 7

Related Products ........................................................................ 8

Connections .............................................................................. 11

Particle Level Explanation: Comprehension Goals ................. 13

Sample Data Analysis and Calculations .................................. 13

Answers to Big Idea Questions ................................................ 14

Resources .................................................................................. 15

Student Sheets* ....................................................................... S-1

*Photocopy the Student Sheets as needed for use in your classroom.

©2016 Carolina Biological Supply Company/Printed in USA.

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Table of Contents

TEACHER’S MANUAL

Correlation to the Next Generation Science Standards ...3

Overview ...........................................................................4

Learning Objectives ..........................................................4

Time Requirements ..........................................................4

Materials ...........................................................................5

Safety ................................................................................5

Notebooking ....................................................................5

Preparation .......................................................................6

Procedure ..........................................................................7

Presentations ....................................................................9

Answers to Questions in the Student Guide ..................9

Extension Activities ........................................................11

Design Challenge Scoring Rubrics .................................13

Grading Rubric ...............................................................14

STUDENT GUIDE*

Background and Comprehension Questions ...............S-1

Warm-Up Activity ..........................................................S-2

Design Challenge ..........................................................S-4

Design Challenge Questions .........................................S-6

Race Car Template .........................................................S-7

*Photocopy the Student Guide as needed for use in your classroom.

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Cover image ©2013 Jupiterimages Corporation


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Carolina STEM Challenge®: Balloon Race Cars Teacher’s Manual

3©Carolina Biological Supply Company/Printed in USA.

To view additional national and local standards met by this kit, visit www.carolina.com/correlations.

Correlation to the Next Generation Science Standards

Category Background Activity Questions Extensions

Science and Engineering Practices

Asking Questions and Defining Problems ¿ ¿

Planning and Carrying Out Investigations ¿ ¿

Analyzing and Interpreting Data ¿ ¿

Constructing Explanations and Designing Solutions ¿

Obtaining, Evaluating, and Communicating Information ¿

Crosscutting Concepts

Cause and Effect: Mechanism and Prediction ¿ ¿ ¿

Systems and System Models ¿ ¿

Structure and Function ¿ ¿

Core Ideas: Physical Sciences

HS PS2.A: Forces and Motion ¿ ¿ ¿

Core Ideas: Engineering, Technology, and Applications of Science

HS ETS1.A Defining and Delimiting an Engineering Problem ¿ ¿ ¿

HS ETS1.B Developing Possible Solutions ¿ ¿ ¿

HS ETS1.C Optimizing the Design Solution ¿ ¿ ¿

HS ETS2.A Interdependence of Science, Engineering, and Technology ¿

Source: NGSS Lead States. 2013. Next Generation Science Standards: For States, By States. Washington D.C.: The National Academies Press.

*”Next Generation Science Standards” is a registered trademark of Achieve. Neither Achieve nor the lead states and partners that developed the

Next Generation Science Standards was involved in the production of, and does not endorse, this product.

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Teacher’s Manual Carolina STEM Challenge®: Balloon Race Cars

©Carolina Biological Supply Company/Printed in USA.©Carolina Biological Supply Company/Printed in USA.

OverviewIn this series of hands-on activities students learn about Newton’s laws of motion by designing, building, and observing balloon-powered race cars. Students develop their engineering and critical thinking skills by working in teams to find creative solutions to a design challenge presented to the class in a competitive format. First, students perform a Warm-Up Activity during which they assemble balloon-powered race cars out of a foam tray, a balloon, and straws. Students measure the distance the balloon racers travel. During the Design Challenge, students brainstorm ways that the race car design can be modified to meet a specific challenge, such as traveling farthest or traveling fastest. They make modifications to the basic design, based on their knowledge of Newton’s laws of motion, and then enter their engineered race cars into a classroom competition, which can be scored using the Design Challenge Scoring Rubric. A Grading Rubric also is provided in the Teacher’s Manual, facilitating assessment of each team’s results. Team presentations allow students the opportunity to reflect on their experience and demonstrate their learning in creative ways. Assessment questions and STEM-based extension activities are also included. This kit supports 15 teams of two or three students each.

Learning ObjectivesStudents will

•examine applications of Newton’s three laws of motion.

•build a balloon race car.

•draw force diagrams.

•design and build a balloon-powered race car, competing to build the race car that travels the fastest or the farthest.

Time RequirementsTeacher Preparation ............................................. 45 minutes

Background and Comprehension Questions ......... 50 minutes

Warm-Up Activity................................................. 50 minutes

Design Challenge* ............................................... 50 minutes

Presentations* ..................................................... 50 minutes

*The time required to complete this portion of the lab may vary. Establish a time limit that fits your classroom scheduling needs.


Balloon Race Cars

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©Carolina Biological Supply Company/Printed in USA.©Carolina Biological Supply Company/Printed in USA.

Materials

Included in the kit:

30 9″ balloons

30 foam trays

100 straws

250 wooden stirrers

32 5″ balloons

8 cardboard trays (can be cut as needed)*

4 sheets of sandpaper

1 lb of modeling clay

35 plastic stirrers

Teacher’s Manual and reproducible Student Guide

Needed, but not supplied:

15 rolls of tape

15 scissors

15 metric rulers

15 or more timers

15 resealable plastic bags

5 or more metersticks

Optional for the Design Challenge (not supplied):

other objects to construct wheels (e.g., CDs, plywood, bottle caps)

other materials for the car body (e.g., plywood, cardboard)

11″ balloons

balloons of other shapes (e.g., long, pear-shaped)

*Note: Eight large trays are provided for potential use by 15 teams. To ensure that each team has access to a cardboard tray during the Design Challenge, cut the trays in half and distribute them.

Otherwise, present the trays as a limited resource that might or might not be incorporated into a given team’s design. Some teams may choose not to use the cardboard in their designs.

SafetyUse this kit only in accordance with established laboratory safety practices, including appropriate personal protective equipment (PPE). Have students wear protective eyewear when working with the balloon racers in case the balloons pop. Ensure that students understand and adhere to established laboratory safety practices. Know and follow all school district guidelines for the disposal of laboratory wastes.

To minimize the spread of germs, be sure that only one student inflates each balloon. Students with a latex allergy or latex sensitivity should not work with the balloons.

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©Carolina Biological Supply Company/Printed in USA.

NotebookingHave students compile all their work into a single notebook. Notebooking provides students a complete and tangible record of their project. Students can use their notebooks to organize their notes, document their processes, complete their assignments, review their lessons, and prepare for assessments.

Margin notes throughout this Teacher’s Manual provide specific instructions on how to help your students achieve success through Notebooking. These margin notes and the optional Study Tips below are designed to help students improve literacy, explore creative ideas, strengthen their critical thinking and analytical skills, and practice data collection and interpretation through the Notebooking process.

Study Tip 1: Have student write the boldfaced key words and their definitions in the Background section of their notebook. Have students draw a picture illustrating the meaning of each word or applying it correctly in context. This may help students remember the word and associated concepts.

Study Tip 2: Have students reserve a page in their notebook for brainstorming and planning during the Design Challenge. Have them note the number, type, and size of the materials they wish to use, and describe how they interact. On this page they might also include drawings and schematics, brainstorming notes, or inspirational text and images.

Study Tip 3: Have students record their observations, changes to their designs, and data in real time, i.e., as it happens. This ensures that all their thoughts, impressions, and data are documented. Later, they can organize and refine this information on subsequent pages.

Preparation

Warm-Up Activity

1. Familiarize yourself with the contents of the Teacher’s Manual and the Student Guide. It may be helpful to perform a walk-through of the Warm-Up Activity before class, while students are absent.

2. a. Photocopy the Student Guide for each student. Photocopy the Race Car Template for each team.

b. If you plan to use them, photocopy the Grading Rubric and the Design Challenge Scoring Rubrics for each student or team (see the Procedure section for more information on these assessment tools).

3. Locate or ready the materials that are needed for the activity but not supplied in the kit.

4. Cut each sandpaper sheet into four squares of equal size.

5. Set up 15 team workstations, and distribute the following materials to each station:

9″ balloon 1″ ball of clay (placed in a resealable

3 straws plastic bag to prevent dehydration) scissors square of sandpaper

2 wooden stirrers foam tray

metric ruler Race Car Template

roll of tape

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6. In a hallway or along an unobstructed wall, set up at least one racetrack that is at least 5 meters long. Make sure the surface is smooth; avoid carpeted or uneven surfaces. Lay at least 5 metersticks on the floor, end-to-end, in a straight line. If you have additional metersticks and space, use up to 10 to form the racetrack. Tape the metersticks to the floor. Students will release the balloon race cars at the starting point of the line of metersticks (0 cm), so make sure there is adequate room for students to maneuver at the start of the track. Consider setting up the track(s) along a wall, which would provide a boundary on one side to prevent the race cars from running off the race course.

Design Challenge

1. Decide the best approach for your class to plan its activities. Options include the following:

• If you have a block schedule, you might have students begin planning the Design Challenge immediately after performing the Warm-Up Activity. Be sure that students see the materials available and discuss the potential for using additional materials.

• Allow a class day between the Warm-Up Activity and the Design Challenge for teams to plan their design.

• Have teams get together outside class to plan, and then submit their plans to you for approval before the next lab day.

2. Before teams begin building, approve their design plans. Ensure that students are taking adequate safety precautions.

3. Gather the necessary materials, or otherwise arrange for them to be available on the day of the Design Challenge.

4. Set out the materials called for in the students’ plans. Make sure that quantities are sufficient and that teams use only what they need. For example, if several teams plan to make cars from the cardboard trays, ensure that the cuts are planned strategically to allow enough material for everyone. Instead, you may choose simply to cut the cardboard trays in half and supply a half-tray to each team.

5. If necessary, reassemble the race track(s) from the Warm-Up Activity as described in the Warm-Up Activity preparation.

Procedure

Warm-Up Activity

1. Distribute the Background and Warm-Up Activity pages to each student. Assign the Background reading and the accompanying Comprehension Questions to students to complete either in class or as homework.

2. Divide the class into 15 pairs or small groups. Adjust the sizes of the 15 teams according to the needs of your classroom.

3. Monitor students as they assemble the race cars. For safety and hygienic reasons, assign one student in each pair to inflate the balloon. Ensure they are using the materials safely.

Notebooking Tips

➤ Have students reserve a page at the front of their notebook for a Table of Contents, which will list the order and location of specific components of the assignment. At the end of the project, have students number the notebook pages and complete the Table of Contents.

➤ For students using bound notebooks, have them paste the photocopied Background page on the left side of a 2-page spread, and write their answers on the right-hand page. For students using loose-leaf notebooks, have them hole-punch the background page along its right-hand margin and then insert it as the left-hand page of a 2-page spread. Have them write their answers on the right-hand page.

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4. Distribute the Design Challenge pages to each student, and have the teams complete the Brainstorming activity.

5. Students will encounter several challenges in building balloon-powered race cars. If not properly stabilized, the cars will tend to travel at an angle or in a circle. This may also occur if the wheels are not parallel to the body of the car, or if the straw releasing air from the balloon is not parallel to and centered on the body of the car. After the activity, discuss the challenges students encountered while building and testing their race cars. Have students brainstorm possible solutions based on the information in the Background section and their knowledge of Newton’s laws of motion.

Design Challenge

1. Assign each team a design challenge. Possibilities include the following:

a. Design a race car that travels the greatest distance.

b. Design a race car that travels at the greatest speed.

2. Share your expectations of student performance. A Grading Rubric and Design Challenge Scoring Rubrics have been provided in this Teacher’s Manual. If you plan to use these rubrics, provide a copy to each student or team, and review your expectations with the class.

3. If necessary, guide students’ design proposals by providing them with the following prompts:

• What forces are acting on the race car?

• Which of these forces should be minimized, and which should be maximized?

4. Approve each team’s design plan before allowing students to begin building and testing their designs. Ensure that students have identified and are following safety protocols including wearing the proper personal protective equipment.

5. Moderate the competition. If competing for speed, students will measure the time it takes the race car to travel a distance of 1 meter. Students will use this measurement to calculate the rate of travel.

6. Administer the Design Challenge Questions.

7. Facilitate the team presentations. For ideas on how presentations can be conducted, refer to the Presentations section.

8. a. Evaluate each team’s performance in the competition portion of the Design Challenge using the appropriate Design Challenge Scoring Rubric. This rubric should not be used to determine students’ grades, but as a means for comparing the designs of different teams. Teams should be evaluated for performance of the task as well as creativity in problem solving.

b. Evaluate each team’s performance on the assigned tasks using the Grading Rubric. You may wish to adjust how each component is weighted based on the focus of the activity, your objectives, and students’ needs.

Notebooking Tips

Have students record their design brainstorm on a discrete page in their notebooks. Information developed using the Design Guide, along with descriptions and finalized drawings, should appear on the page that follows the design brainstorm page.

Have students dedicate one or two pages of their notebook to preparing their proposal based on the questions in the Design Guide. Before they proceed, have them submit these pages for your approval. Review each design and offer assistance as appropriate.

For students using bound notebooks, have them paste the photocopied Design Challenge Questions page on the left side of a 2-page spread, and then write their answers on the right-hand page of the spread. For students using loose-leaf notebooks, have them hole-punch the Design Challenge Questions page along the right-hand margin and insert the page on the left so they can compile their answers on the right-hand page.

After students have answered the questions, have them finalize their notebook’s Table of Contents. Have them number every page in a specific location, and complete their Table of Contents by listing each part of the assignment and its corresponding page number.

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Presentations After students have completed the competition portion of the Design Challenge and answered the Design Challenge Questions, have the teams present their designs and results to their classmates. A variety of creative formats can be utilized, many of them incorporating technology. Consider having students make their presentations using computer software, videos, interactive whiteboards, blogs, and other multimedia.

Alternatively, have student groups present their lab reports using mini posters. A mini poster can be created from a tri-folded 11” × 17” sheet of paper or from two overlapping file folders glued or taped together. Teams might also display their findings in the form of traditional posters, as collages, in newspaper- or magazine-style formats, or through other creative means.

Each presentation should include the team’s design, the design features, and students’ results and reflections for improving their team’s design. Encourage peer review by having each team view another team’s work and provide feedback before the presentations are made to the larger, classroom audience.

Answers to Questions in the Student Guide

Comprehension Questions

1. Provide two examples of Newton’s first law of motion that you have observed firsthand.

Answers will vary. Two examples of objects remaining at rest include a book sitting on a table and a stalled car stopped on a level road. Two examples of objects in motion include a skateboard rolling across pavement and a rock rolling downhill.

2. Imagine that you are going on a road trip, and you set the cruise control on your car to 60 miles per hour (mph). The road is level and straight, so over the next mile, the car maintains a steady speed of 60 mph. What is the acceleration of the car? Why is this so?

The acceleration of the car is 0 m/s2, because the velocity of the car did not change.

3. Draw a picture of a rocket in motion. Illustrate Newton’s third law of motion, and draw arrows showing the direction of the equal and opposite forces (F

propulsion

and Fapplied

) acting on the rocket, which result in its forward motion.

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Sample Data from Warm-Up Activity

Trial 1 Trial 2 Trial 3Average Distance

Distance (cm)

344 230 280 285

Sample Brainstorming

Consider the race car that you built and the materials that you used in the Warm-Up Activity. What are some things that you could change about the race car that might affect how well it worked? List at least three things that you could change.

Answers will vary, but possibilities include:

Body: dimensions, shape (square, round, triangular), material

Wheels: size, placement on car body, material, number

Balloon: size, inflation, number of balloons

Straw: length of axles, length of straw in balloon, size of straw, number of straws in balloon, type of straw

Design Challenge Questions

1. Now that you have seen several teams’ designs for balloon race cars, what can you conclude about why the successful designs worked?

Answers will vary. Successful balloon-powered race cars will minimize friction and maximize propulsion, while maintaining directional control and remaining on the ground. In the sample laboratory trials, race cars with longer bodies and larger, well-stabilized wheels outperformed other cars in the distance challenge.

2. How did you modify the race car, and what were the results of each change you made?

Answers will vary. In the sample trials, cars with shorter bodies or larger wheels alone traveled shorter distances, and the rear wheels often were lifted off the ground by the force of propulsion. Cars with a heavier body traveled a straighter path. Cars with a heavier body and larger wheels traveled a straighter path and went farthest. Cars with a thicker body and larger, thicker wheels traveled shorter distances or did not move at all. A smaller balloon resulted in shorter distances traveled.

3. What changes or modifications would you make to improve your design if you were to try again? What effect will these changes have? Why?

Answers will vary. Students should indicate an understanding of the successful designs they observed and how these concepts could be applied to their own balloon race cars.

4. Concept cars are vehicles that incorporate new technologies and innovative designs. One such concept is the hover car, a vehicle that floats above the surface of the road rather than having wheels that touch the ground. Hover cars have been built, but have never gone into mass production. In terms of Newton’s laws of motion, what are the advantages and disadvantages of a hover car?

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One advantage is that, because hover cars lack wheels, the friction between the roadway and the wheels of the car is eliminated. This touches on Newton’s second law, in that friction acts to slow the velocity of a rolling object (such as tires). However, even hover cars must overcome air friction, and they also have to overcome the force of gravity by applying a source of upward propulsion, which is a disadvantage.

Extension Activities 1. Have students read an article relevant to the topic being studied. An

appropriate resource is provided below. However, you may prefer to have students read about a local current event or another article relevant to your students. While students are reading, you may wish to have them also perform one or more of the following literacy-building exercises:

•summarizeeachparagraphinasinglesentence

•explaindiagramsandpicturesintheirownwords

•circleorunderlineunfamiliartermsandhavethemlookthemup

•underlinethemainideaofeachparagraph

•summarizethearticleinasingleparagraph

•createagraphicorganizer(e.g.,Venndiagram,flowchart,ortimeline)that summarizes concepts or shows the relationship between the main points of the article

“One-Third of Car Fuel Consumption Is Due to Friction Loss.” ©Science Daily This online article from Science Daily (12 Jan. 2012) summarizes an article, “Global energy consumption due to friction in passenger cars,” by K. Holmberg, P. Andersson, and A. Erdemir and first published byVTTTechnicalResearchCenterofFinlandinTribiology International (Volume47,March2012,pages221–234). http://www.sciencedaily.com/releases/2012/01/120112095853.htm

Science Extensions

2. Have students research the development and use of rockets in space exploration. Have students apply Newton’s laws of motion to spacecraft movement, drawing and labeling their representations.

3. Have students race the cars using a gas-producing reaction to fill the balloon (e.g., vinegar and baking soda or an effervescent tablet and water)

4. Have students draw a force diagram of all the forces acting on the balloon-powered race car in motion. To draw a basic force diagram, first draw a picture of the race car, then draw an arrow pointing in the direction each force is exerted on the race car. The length of the arrow correlates with the magnitude of the force; the longer the arrow, the stronger the force.

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Technology Extensions

5. In a speed challenge, incorporate a photogate to time the cars as they cross a predetermined finish line on the track.

6. Have students use computer-assisted design software to design a new race car template.

Engineering Extensions

7. Have students focus on examining the types of forces that can be used to propel the race cars. In addition to the balloons, students might use their hands, ramps with different inclines, springs, large rubber bands, or other means of propulsion.

8. Have students examine the effect of friction on the velocity of the race cars. Have students test their race cars on a smooth surface such as a tile or hardwood floor, and then again on carpet, linoleum, or concrete. Then, have students compare the car’s velocity on each surface and draw conclusions on the basis of their results.

Math Extension

9. Have students graph the distance their balloon-powered race car traveled over time in the Warm-Up Activity and each of their trial runs during the Design Challenge. To do so, students should take measurements at multiple points (for example, at 0.5 m, 1 m, 1.5 m, 2 m, etc.). Additional stopwatches or photogates will be needed in order to conduct this extension.

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Speed

Criterion 1. Beginning 2. Developing 3. Proficient 4. Exemplary

Performance of Design Challenge Task

Team constructed a race car that did not travel.

Team constructed a race car that traveled up to 0.5 m/s.

Team constructed a race car that traveled between 0.5 and 1.5 m/s.

Team constructed a race car that traveled faster than 1.5 m/s.

Creativity Team used the Warm-Up Activity race car with no design modifications.

Team used the Warm-Up Activity race car with only minor design modifications.

Team used the Warm-Up Activity race car with several design modifications.

Team utilized materials that were not listed and successfully designed a different race car model than that used in the Warm-Up Activity.

Distance

Criterion 1. Beginning 2. Developing 3. Proficient 4. Exemplary

Performance of Design Challenge Task

Team constructed a race car that did not travel.

Team constructed a race car that traveled less than 2 m.

Team constructed a race car that traveled between 2 m and 4 m.

Team constructed a race car that travelled farther than 4 m.

Creativity Team used the Warm-Up Activity race car with no design modifications.

Team used the Warm-Up Activity race car with only minor design modifications.

Team used the Warm-Up Activity race car with several design modifications.

Team utilized materials that were not listed and successfully designed a different race car model than that used in the Warm-Up Activity.

Design Challenge Scoring Rubrics

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Grading RubricGrading Rubric

Component 1. Beginning 2. Developing 3. Proficient 4. Exemplary

Brainstorming Team did not developideas that pertainedto the Warm-UpActivity.

Team developed ideasthat partiallypertained to theWarm-Up Activity.

Team developed ideasthat pertained to theWarm-Up Activity.

Team developedcreative ideas thatpertained to theWarm-Up Activity.

Design andSchematics

Team did not presentwritten instructions orschematics pertainingto the designchallenge.

Team presented eitherwritten instructions orschematics that wereunclear or incompletebut pertained to thedesign challenge.

Team presentedwritten instructionsand schematics thatwere clear andpertained to thedesign challenge.

Team presentedwritten instructionsand schematics thatwere clear, verydetailed, andpertained to thedesign challenge.

Safety Team did not identifysafe lab practices andpersonal protectiveequipment, or usedunsafe lab practices.Team activity wasstopped to correctsafety issues.

Team identified mostsafe lab practices andpersonal protectiveequipment needed.Some teacherintervention wasrequired to ensurestudent safety.

Team identified allsafe lab practices andpersonal protectiveequipment needed.Minimal teacherintervention wasrequired to ensurestudent safety.

Team identified allsafe lab practices andpersonal protectiveequipment needed;these were used at alltimes during theactivity. No teacherintervention wasrequired to ensurestudent safety.

DesignImplementation

Team constructed amodel that did notpertain to the designchallenge.

Team constructed amodel that somewhatpertained to thedesign challenge.

Team constructed amodel that met thecriteria of the designchallenge.

Team constructed amodel that exceededthe criteria of thedesign challenge.

Testing andData Collection

Team did not useappropriateprocedures to testtheir design, collectrelevant data, anddocument changes totheir design.

Team did not useappropriateprocedures to testtheir design, butcollected relevant dataand/or documentedchanges to theirdesign.

Team usedappropriateprocedures to testtheir design. Teamcollected relevant dataor documented somechanges to theirdesign.

Team usedappropriateprocedures to testtheir design, collectedrelevant data, anddocumented allchanges to theirdesign.

Presentationand Reflection

Team presentedmethods and results in an incomplete and unclear manner,and did not reflect on choices.

Team presentedmethods or results inan unclear manner, ordid not reflect onchoices based onscientific principles.

Team presentedmethods and resultsadequately. Teamreflected on choicesbased on scientificprinciples most of the time.

Team presentedmethods and resultsclearly and accurately.Team always reflectedon choices based onscientific principles.

Student GuideNAME

DATE


Balloon Race Cars

S-1©2016 Carolina Biological Supply Company/Printed in USA.

Background

Engines roar as the flag waves, signaling the start of the race. Tires squeal and smoke as they fight the friction of the asphalt and propel the cars forward. The cars speed down the straight quarter-mile track, reaching 50… 100… 200 miles per hour, moving faster and faster! After crossing the finish line, parachutes help the cars slow again to a stop. Race cars are an exciting example of Newton’s laws of motion in effect.

A force is a push or a pull exerted on an object. Some forces are apparent. For example, your hand exerts force on a pencil when you write. Other forces are less obvious; you do not feel the gravitational force that the earth exerts on your body, yet this force keeps you grounded on the surface on the planet. Sir Isaac Newton studied and described the ways in which forces affect the motion of objects. His conclusions have come to be known as Newton’s laws of motion.

Newton’s first law of motion, also known as the law of inertia, states that an object in motion will remain in motion until an outside force acts upon it, and that an object at rest will remain at rest until an outside force acts upon it. Inertia is the resistance of an object to change in its motion. A cup sitting on a countertop demonstrates Newton’s first law of motion. The cup will remain motionless on the countertop until it is picked up, slid across the counter, knocked over, or otherwise acted on by an outside force.

Newton’s second law of motion equates the net force acting upon an object with the product of its mass and acceleration (F = ma). Acceleration is the rate of change in velocity an object undergoes over time, often measured in meters per second squared. For example, when the speed of a car is increasing, its acceleration is positive. If its speed is decreasing, the car’s acceleration is negative. If the speed of a car is not changing, its acceleration is 0 m/s2. The acceleration of an object is affected by its mass. More mass causes less acceleration, and less mass results in greater acceleration. This law also introduces the concept of friction as an external force that acts upon objects. Friction is the force that opposes the sliding motion of two objects in contact, resulting in a loss of velocity. For instance, if you push a skateboard on a flat surface, it will eventually roll to a stop due to friction. In this case, the friction is caused by the contact of the wheels rolling over the floor and the contact of the wheel with the axle. The force of friction can vary according to the kind of surface and the strength of the force pressing the surfaces together.

Newton’s third law of motion states that when one object exerts force on another object, the second object exerts an equal (in magnitude) and opposite (in direction) force on the first. This can be observed in rockets, as the jet of hot gases rushing out causes the rocket to be propelled forward.

Comprehension Questions

1. Provide two examples of Newton’s first law of motion that you have observed firsthand.

2. Imagine that you are going on a road trip, and you set the cruise control on your car to 60 miles per hour (mph). The road is level and straight, so over the next mile, the car maintains a steady speed of 60 mph. What is the acceleration of the car? Why is this so?

3. Draw a picture of a rocket in motion. Illustrate Newton’s third law of motion, and draw arrows showing the direction of the equal and opposite forces (Fpropulsion and Fapplied) acting on the rocket, which result in its forward motion.

Student GuideNAME

DATE


Balloon Race Cars

S-1©2016 Carolina Biological Supply Company/Printed in USA. S-2

Student GuideNAME

DATE


Balloon Race Cars

Warm-Up Activity

Materials

9″ balloon clay

3 straws sandpaper

scissors timer

2 wooden stirrers foam tray

metric ruler Race Car Template

roll of tape

Procedure

1. Cut out the race car body and wheel patterns from the Race Car Template.

2. Tape the race car body pattern to a corner of the foam tray, and use the pattern to cut out a race car body made of foam.

3. Tape the wheel template near a corner of the foam tray. Use the pattern to cut out a wheel.

4. Reuse the wheel template to cut out three more wheels from the foam tray.

5. Use the sandpaper square to sand off uneven edges of the wheels so that they will turn smoothly.

6. Obtain two straws. Measure and cut each straw to a length of 12 centimeters.

7. Use the ruler to measure 2.5 centimeters in from each short end of the foam race car body. Tape the straws across the car body at the 2.5-cm point, as shown. Be sure to align and center the straws so that an equal length of straw extends from each side of the race car body.

8. Carefully press a wooden stirrer through the center of a foam wheel until a 0.5-cm length of the stirrer protrudes on the other side of the wheel. Repeat this process with the second wooden stirrer and a second wheel.

9. Slide the long end of one wooden stirrer through one of the straws attached to the race car body. Then, slide the other wooden stirrer through the other straw.

10. Press a foam wheel onto the free end of each wooden stirrer, so that your race car has four wheels, each positioned 0.5 cm in from the tip of the stirrer.

S-1©2016 Carolina Biological Supply Company/Printed in USA. S-3

11. To help stabilize the wheels and prevent them from wobbling on the axle, roll a small ball of clay between your forefinger and thumb, and then mold the clay around the axle on the outside of each wheel. Use the clay to press the wheel closer to the straw, but not tight against the straw, so that the wheel rolls freely but does not wobble.

12. Cut the third straw to a length of 10.5 centimeters. Insert half the length of the straw into the mouth of a deflated balloon.

13. Securely tape the balloon to the straw so that no air can escape. First, grasp the neck of the balloon, with the straw in your palm and the balloon in your fingers. Without crushing the straw, wrap a piece of tape around the neck of the balloon above the area you are holding. Wrap another piece of tape just below the first. Wrap a third piece of tape around the neck of the balloon where it meets the straw, forming an airtight seal.

14. Test to see that no air is escaping the balloon.

a. Designate one (and only one) person in your team to inflate the balloon.

b. The designated lab partner should inflate the balloon by blowing air through the straw.

c. If you can hear or feel air escaping, add tape around the balloon and straw until no air is escaping.

15. Determine the front and rear ends of the race car. Orient the straw so that it extends from the rear of the race car body, and tape the straw to the body of the car.

16. Move to the track. Inflate the balloon by blowing through the straw. Bend or squeeze the straw to keep air from escaping.

17. Place the front wheels of the race car just behind the starting line of the track.

18. In one movement, release the bent straw and the car, and then watch it as it travels down the track.

19. Observe how the race car travels. Is it traveling in a straight line, or in a curved or circular path? Measure how far the car travels down the track and record this distance (in centimeters) in the following table. If the race car becomes stuck along the edge of the track, record its stopping point as the distance traveled. If the race car exits the track, record its point of departure as the distance traveled.

20. Perform two more trial runs with the race car. Each time, measure and record (in the table) the distance the car travels. Then, calculate the average distance that the race car traveled and record that, also.

Trial 1 Trial 2 Trial 3 Average Distance

Distance (cm)

Carolina STEM Challenge®: Balloon Race Cars Student Guide

Student GuideNAME

DATE


Balloon Race Car Design Challenge


Brainstorming

Consider the race car that you built and the materials that you used in the Warm-Up Activity. What are some things that you could change about the race car that might affect how well it worked? In your notebook, list at least three things that you could change.

Materials

9″ balloon metric rulers

5″ balloons roll of tape

scissors clay

foam tray sandpaper

straws timer

wooden stirrers cardboard tray (may need to cut and share)

plastic stirrers

Other materials may be available. Consult with your teacher.

Design Guide

Planning

1. Describe your design challenge.

2. Design a balloon-powered race car that meets the requirements of your design challenge. In your design plan, use words and pictures to describe the race car you will build.

3. List the equipment and materials you will need to build your race car. For each, also list the quantity you will need.

4. Describe the step-by-step procedure you will follow to build your race car and conduct the test of your prototype.

5. Describe the steps you will take to ensure your own safety and the safety of your team. List the safety equipment you will use and the safety procedures you will follow.

6. List the things you will measure as you conduct your tests.

7. Describe how you will know that you met or exceeded your design challenge goals.

8. Plan how you will present your findings.

S-4

S-5

Building

1. Get approval from your instructor before starting to build your prototype.

2. Based on your design and procedures, build a prototype of your race car.

3. If you discover that changes must be made as you build your prototype, record the modifications to your design.

4. Test your prototype. Record the results of your tests.

5. If the test of your prototype shows that changes must be made to your race car, make the modifications to your design.

6. Record the modifications that you made to your design and whether you think the changes made to your design were successful or unsuccessful, and why.

7. Enter your team’s design in the classroom competition.

8. Answer the Design Challenge Questions.



Student GuideNAME

DATE


Balloon Race Cars

S-6

Design Challenge Questions

1. Now that you have seen several teams’ designs for balloon race cars, what can you conclude about why the successful designs worked?

2. How did you modify the race car, and what were the results of each change you made?

3. What changes or modifications would you make to improve your design if you were to try again? What effect will these changes have? Why?

4. Concept cars are vehicles that incorporate new technologies and innovative designs. One such concept is the hover car, a vehicle that floats above the surface of the road rather than having wheels that touch the ground. Hover cars have been built, but have never gone into mass production. In terms of Newton’s laws of motion, what are the advantages and disadvantages of a hover car?



Race Car Template


Carolina STEM Challenge®:

Balloon Race Cars

Teacher’s Manual and Student Guide

750040

Carolina Biological Supply Company

2700 York Road

Burlington, North Carolina 27215

Phone: 800.334.5551

Fax: 800.222.7112

Technical Support: 800.227.1150

www.carolina.com

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