MECHANICAL MONSTERS
Teacher’s Guide Notes
Junkyard Wars
In a 45-minute class period, you will not have enough
time to show an entire episode and have students work
on their reproducibles. You may show the first segments
and allow students to make hypotheses, answer questions, and evaluate some program events. Show the final
segment featuring the outcome of the program challenge during the next class period.
This popular television show is anything but trashy
entertainment. Each episode takes place in a huge,
specially constructed junkyard, where two teams
of engineers and mechanics get 10 hours to build
machines scrounged from junk. Later the teams put
their contraptions to the test in a competition. Viewers
watch as the teams work to meet the same challenge
in different ways.
In 60-minute class periods, you can show an entire
episode and take sufficient time for students to complete their reproducibles. In 90- to 120-minute blocks,
you can also conduct one of the four Classroom
Challenges (laboratory experiments, projects, and
demonstrations) included herein.
First comes a challenge: Build an object to perform
a specific task. Then the teams swing into action,
struggling to beat the clock. They revise their plans as
necessary. Throughout the show, an expert gives opinions and evaluations of projects. The hosts make
diagrams to describe engineering principles behind
each team’s efforts.
You may start some Classroom Challenges before
or after you show the videos in class. You will want to
assign the more substantial challenges after watching
the videos.
Using the Videos
Each of the enclosed two videos (about 45 minutes
each) features an episode of Junkyard Wars. On the
following page are onscreen discussion questions for
students to discuss and answer. These and additional
questions for students are on the reproducible pages
at the end of this teacher’s guide.
It is helpful to keep some classroom lights on while
watching a video so students can answer the onscreen
discussion questions and make drawings on the
reproducible pages. Pause the video when these
questions appear.
1
Teacher’s Guide Notes (cont.)
Episodes in This Kit
Episode I: Jumbo Trucks
Episode II: Climbing Car
After Segment 1 (5:32)
Compare the designs developed by the experts.
Sketch and describe each team’s basic design.
Look for evidence of teamwork during the video.
Are conflicts resolved successfully?
Episode challenge: Build a monster truck.
Program overview: Big-wheeled trucks race an obstacle-filled course before driving over a row of vehicles.
Episode II: Climbing Car
Episode challenge: Build a machine that quickly
ascends a steep incline.
Program overview: A sand rail gets new power and a
rebuilt mail truck transforms into an amazing machine.
After Segment 2 (19:28)
With five hours remaining, which team is further
ahead in their construction?
How have the teams’ plans changed because
of materials or time limitations?
Target Grades: 6--12
Curriculum Focus: physics, physical science,
auto mechanics, drafting and design
Scientific Principles: kinematics, dynamics, power,
momentum, gradient
After Segment 3 (31:59)
In your opinion, which team has the best-built
climbing car? Which team has the best overall
design? Give evidence to support your answers.
Predict which team you think will have the fastest
car. Which team do you think will make it farther
up the hill? Give reasons for your choice.
Onscreen Discussion Questions
(Note: Pause the video so students can answer questions on
the reproducibles found on pages 14 and 15 in this teacher’s
guide. To match the time codes below, set your VCR counter
to zero at the beginning of the tape.)
Safety Considerations
Episode I: Jumbo Trucks
After Segment 1 (4:48)
A jumbo truck must ride over large bumps, including
crushed cars. What materials will the teams search
for in the junkyard? Sketch a general design that
shows where those parts will be used.
Look for evidence of teamwork during the video.
Are conflicts resolved successfully?
Please do not send your students into junkyards for
these or any other projects! Designing and building
objects is a great way for students to learn engineering
skills and apply science and design principles, but you
must give them ways to do this safely.
Some options:
Provide materials and building time in class
(especially for younger students).
Allow students to purchase their supplies or use
supplies from around the house (with permission,
of course) within strict guidelines set up in advance,
including types of materials and cost.
Encourage parents to teach their children correct use
of tools, forbidding all power tool use except while
an adult is present. Never use welding torches or
chain saws!
After Segment 2 (21:54)
With three hours remaining, how have the teams’
plans changed because of materials or time
limitations?
What are the problems you see with each team’s
construction so far?
After Segment 3 (33:07)
In your opinion, which team has the best-built jumbo
truck? Which team has the best overall design?
Give evidence to support your answers.
Predict which team you think will have the fastest
truck. Give reasons for your choice.
2
The general rubric titled “Indicators of Student
Involvement” is designed to be used for Classroom
Challenges #1-3. Realistically, you can evaluate two
to four students per lab period. During the course of
a quarter, make sure every student is evaluated at least
once. But here’s the key: Don’t let the students know
who is being observed in any particular lab period.
Do not assign projects that use explosives, very large
forces, extremely high air pressures, or unprotected
sharp objects. Consider all the worst-case scenarios and
set your guidelines accordingly. As a general principle,
design projects that are based on finesse or accuracy
instead of raw power.
Assessments
For the climbing-car project, feel free to weight the
different criteria shown along the left column as you
see fit. You may wish to emphasize or de-emphasize
the importance of the journals, or replace the journals
with formal lab reports or technical drawings. You may
also wish to replace the numerical goals for the students
(the “surviving” angles) with a more general ranking
among the projects in your class that year.
Included in this guide are two assessment rubrics: one
for the general evaluation of students in laboratory
situations and one for the Calculating Gradient
project. Make a transparency or copy of the rubrics
to share with students ahead of time; they must know
the criteria on which they will be evaluated.
National Science Education Standards
National Council of Teachers of Mathematics
The National Council of Teachers of Mathematics
(NCTM) has developed national standards to provide
guidelines for teaching mathematics. To become a mem ber of the NCTM, or to view the Standards online, go to
http://www.nctm.org.
This lesson plan addresses the following math standards
for grades 9–12:
Algebra Standard: Understand patterns, relations,
and functions; represent and analyze mathematical
situations and structures using algebraic symbols;
use mathematical models to represent and understand
quantitative relationships; analyze change in
various contexts.
Measurement Standard: Understand measurable
attributes of objects and the units, systems and
processes of measurement; apply appropriate
techniques, tools, and formulas to determine
measurements.
The National Science Education Standards, published
by the National Academy of Science, provide guidelines
for teaching science in grades K–12, as well as a
coherent vision of what it means to be scientifically
literate. To order the Standards, contact the National
Academy Press, 2101 Constitution Ave. NW, Lockbox
285, Washington, DC 20005; http://books.nap.edu.
The activities in this teacher’s guide address the
following national content standards:
Science as Inquiry (grades 5–12)
Abilities necessary to do scientific inquiry
Understandings about scientific inquiry
Physical Science (grades 5–8)
Properties and changes of properties in matter
Motions and forces
Transfer of energy
Physical Science (grades 9–12)
Structure of atoms
Structure and properties of matter
Chemical reactions
Motions and forces
Conservation of energy and increase in disorder
Interactions of energy and matter
Science and Technology (grades 5–12)
Abilities of technological design
Understandings about science and technology
3
CLASSROOM CHALLENGES
#1: CENTER OF MASS: A BALANCING ACT
Background Information
Demonstrations:
The center of mass of a human varies with body type
and position. But when standing, a person’s center of
mass typically runs along the center of the body a bit
above the navel. On average, men have a higher center
of mass than do women. Use the following fun stunts
to demonstrate the center of mass.
The center of mass of an object is the location of the
average of all the mass that makes up the object. Two
examples: The center of mass of a billiard ball is at the
center of the ball, and the center of mass of a doughnut
is in the middle of the hole. Practice with your students
estimating the center of mass of a variety of everyday
objects in your classroom.
1. Touch your toes. This sounds easy enough: Just
touch your toes without bending your knees. Now
try to touch your toes while standing with your heels
pressed up against a wall. Most people can’t do it.
The reason? To keep the center of mass over your
feet, you must shift your hips backward as you lean
forward. The wall prevents you from shifting your
hips back far enough to keep your balance.
One way to determine the center of mass definitively is
to balance an object. It balances when its center of mass
is in line with its supports. So, if you balance a hammer
by laying it horizontally on your outstretched finger,
you’ll find that its center of mass is closer to the head
of the hammer than halfway along its handle. A person
can balance on one foot if his or her center of mass is
somewhere in a line directly over any point on that foot.
It’s easier to balance on two feet because your center of
mass can be lined up anywhere in the area between or
on your feet, which is a much larger area.
2. Pick up a chair. Another easy thing to do? Try it this
way: Stand with your toes against a wall. Step back,
toe to heel, so that you’re two foot-lengths from the
wall. Have someone put a folding chair between you
and the wall. Now bend at the hips so that your head
is against the wall and your back is nearly horizontal.
Pick up the chair and try to stand up.
Many women can easily do this task, while most
men cannot for two reasons. First, women tend to
have a lower center of mass, so they can shift their
hips back far enough that their center of mass plus
the chair remains over their feet. They can keep their
balance. Having a higher center of mass, most men
can’t shift back far enough to keep their balance.
Secondly, men usually have bigger feet than women,
but that’s not nearly as much fun a reason.
3. Stand on your toes. Again, it sounds easy, but try it
when you are standing with your toes against a wall.
Most of us can’t shift our weight forward far enough
to balance on the smaller toe area.
4
Applications
How does center of mass relate to vehicles? One of
the dangers of driving is the possibility of a rollover.
A dangerous event, a rollover occurs when the center
of mass of a car or truck is no longer over the wheelbase. This may happen on an incline or if a vehicle
shifts as it turns a corner too fast.
In the Climbing Car episode, the distinct danger was
that the cars could tip backwards as they travel up
a steeper and steeper hill. If the front wheels leave
the ground, the center of mass must balance over the
very narrow rectangle bounded by the back wheels.
Otherwise, the car can tumble down the hill.
To keep a car or truck from tipping, a vehicle’s center
of mass must always line up over the rectangle formed
by the four wheels. The risk of a rollover decreases if
that rectangle is very large (larger wheelbase) or if the
vehicle’s center of mass is built as low as possible.
Do not try these demonstrations at home! Drive
safely, and always keep your center of mass over
your supports, where it belongs.
In the videos, the danger of a vehicle tipping over was
very real. In the Jumbo Trucks episode, adding huge
tires to the trucks dramatically raised their centers of
mass. If a truck started to tilt, because it missed one
side of the crushed cars and two wheels were higher
than the others, the truck would easily tip over. In the
diagrams below, the dots represent the centers of mass.
Note that the angle of incline does not have to be very
big for the second truck to tip over because its center
of mass is so high.
Stable Truck
Tipping Truck
5
#2: CALCULATING GRADIENT: A MATH MOMENT
Background Information
In the Climbing Car episode, the hosts talk about
calculating the grade of the hill. Mountain roads often
have signs warning drivers to use caution because the
road has a 6% or 8% grade. Let’s explore this
concept in a bit more detail.
4. If a hill has an angle of 28°, how far will you climb
if you hike a horizontal distance of 400 feet?
Answers:
1. 50 feet
2. 14°
3. 0.077 or 7.7% gradient; 4.4°
4. 213 feet
The gradient of a hill is the height increase, or rise,
in a given horizontal distance, or run, as shown below.
One important use of this concept is in interpreting
topographic maps. A “topo” map shows contour lines
as irregular rings (see map on following page). Contour
lines show areas of identical height or altitude.
Reproduce this map and the questions that follow it
for your students. If you walk along a contour line, the
altitude doesn’t change at all, so the gradient of your
path is zero. If you walk along a path perpendicular
to the contour lines, you’re traveling along the steepest
route, or the one with the highest gradient.
height or rise
horizontal distance or run
So a hill with a 6% (or 0.06) grade has a height change
of 6 feet for every 100 feet of horizontal distance traveled. If they’ve had some trigonometry, students should
recognize that this is related to the tangent function for
right angles. The tangent of the angle in the lower left
corner of the triangle above is given by the following:
tan = rise
run
The map’s contour lines indicate altitude differences
of 10 meters on a hill. A hiker who wants to travel
from the bottom of the hill to the top could take an
infinite number of paths, but we’ve marked two on
the map. Traveling along line A, the hiker would take
the shortest possible path, while Path B is considerably
longer.
For a hill with a 6% grade, the tangent is 0.06. To find
the actual angle of the hill in degrees, use the tan-1 key
on a scientific calculator. The angle is about 3.4°. If
you know the angle, you can use the tan key to find
the gradient.
Give these examples to students to try.
1. A mountain biker struggles up a hill with a 25%
grade. How much does his elevation increase for every
200 feet he travels horizontally?
2. What is the angle of the hill in the diagram above?
3. An engineer designs a ramp that rises 3 feet along
a horizontal distance of 39 feet. Find the gradient
and angle of the ramp.
6
6. So, Path B is longer than Path A, especially if you
include the curved walk around the base of the hill.
But which path would be easier to climb? Briefly
explain which path you would choose.
Answer: Path B is much easier to climb, so those who
prefer a more leisurely stroll would choose B. Those
looking for a strenuous hike would choose Path A.
Using the topo map, answer the following questions:
1. Measure the length of Path A with a ruler and write
its length. (Answer: Assuming length is 1 3/8 inches,
or 138 m)
2. Measure the length of the straight part of Path B
with a ruler and write its length. (Answer: Assuming
length is 3 1/16 inches, or 306 m)
3. Now count how many contour lines are crossed by
Path A. (5 contour lines) Write the corresponding
height increase. (50 m)
4. How does that compare to Path B? How many contour lines are crossed by this path? (5 contour lines)
Write the height increase of Path B. (50 m)
5. To find the gradient of each path, divide the height
increase by the length of the path (the straight part,
for B). Show your calculation, then calculate the
angle for each path.
50 m =of0.362
Gradient
Path A
Angle
of Path
-1 (0.362)
tan
=A
19.9°
50 m =of0.163
Gradient
Path B
-1 (0.163)
Angle
of Path
tan
=B
9.3°
138 m
306 m
7
#3: ENERGY LAB WORK: AN UPHILL BATTLE
Background Information
Procedure
1. Place a clamp on a ring stand about 2/3 of the distance from the bottom. Hold the board in place, resting against the clamp, at an angle of 20° as shown in
the diagram below. Pull the cart up the inclined plane
with a spring scale (which must be kept parallel to
the plane of the board) at a constant velocity. Record
the force required. Measure the distance along the
incline from the bottom to the clamp.
In this work-energy lab, make sure that students
understand that they will keep the height of the top
of the hill constant, so that they measure the length
(d) of the ramp from tabletop level only up to the
clamp, not to the end of the ramp.
Students should find an inverse relationship between
force and distance (the graph is a hyperbola), and the
correct answer to number 3 is therefore that all paths
take the same amount of work (within experimental
error, of course). Friction increases the amount of force
needed for each trial, but not by quite the same amount
each time; it is one of the sources of error in this lab.
20°
30°
40°
50°
60°
Force
(N)
Distance
It is often surprising to students that all the paths up
the hill require the same amount of work and energy.
The difference is really in the force, which most people
equate with effort, and the path length.
(cm)
Purpose
Investigate the force and distance required to move
a car up a ramp.
Materials
board for inclined plane
spring scale
meter stick
ring stand
clamp
cart
protractor
2. Vary the angle while keeping the final height the
same by sliding the board down along the clamp to
make angles of 30°, 40°, 50°, and 60°. Record your
data in the table above.
Analysis
1. Make a graph with distance on the horizontal
axis and force on the vertical axis. Sketch a graph,
including axis labels, title, and large and
small numbers.
2. What relationship do you find between force
and distance?
3. Returning to the pre-lab question, which path
requires the most work and why? Hint: Calculate
the work necessary for each trial in your experiment.
Use this equation:
Pre-lab question: A hill has three paths up its sides
to a flat summit area (D), as seen above. The three path
lengths AD, BD, and CD are different, but the vertical
height is the same. Not including the energy used to
overcome the internal friction of the car, which path
requires the most energy (gasoline) for a car driving
up it? Explain.
work = force x displacement.
4. What role does friction play in this experiment?
8
RUBRIC
Classroom Challenges #1-3
Indicators of Student Involvement
Categories
0-1 point
2-3 points
4-5 points
Intellectual
Curiosity and
Spirit of
Investigation
Fills in lab sheet only
Asks no questions or
irrelevant questions; answers
no questions
Not involved with lab
Does not complete
experiment
Makes effort to understand
the lab
Asks and answers clarifying
questions about the lab
Mostly involved
Completes lab as directed
Passive participation
Strives for complete understanding
Asks and answers probing
questions that extend
understanding
Full, active participation
Goes beyond intended
activity
Personal
Responsibility
Tardy or significant time
wasted
Careless with equipment or
does not handle equipment
at all
Does not follow safety
procedures
Cleans up insufficiently
Unprepared for lab
activity
Time wasted or does not
complete lab
Some carelessness
or risky procedures
Cleans up partially
Makes good or excellent use
of time
Uses lab equipment and
facilities responsibly
Cleans up completely
Prepared for class,
has needed materials
for activity
Group
Dynamics and
Interaction
Does not contribute
to group
Minimal or negative
interactions
Creates or encourages
unrelated activities
or discussions
Some contribution to group
understanding
Mostly receptive to ideas
and opinions of others
Creates some distractions
Contributes to group understanding through questions
or explanations
Makes sure everyone in
group understands
Receptive to ideas and
opinions of others
Makes effort to reduce
group distractions
9
#4: THE CLIMBING CAR
Background Information
Objective
Design and build a Lego car that can ascend the
steepest slope possible.
For this engineering-design project, ask students for
donations of Lego parts (for extra credit, if you’d like).
It’s amazing how much they have of their childhood
toys. Or you can try to collect materials from garage
sales, ask toy-store managers for donations, or write
a small grant to purchase the materials initially.
Fortunately, they can be reused many times.
Rules
The board your car must ascend starts out at a shallow
slope and gradually increases the slope. This continues
until your vehicle fails in some way (stops moving or
tips over).
In making a board with an incrementally increasing
angle, you can use wood or cardboard with flexible
pieces like poster board between the different angle
sections. Or you could make the whole thing out of
a curved piece of flexible plastic for a constantly
increasing angle.
You may not do anything that changes or damages
the board, including using anything on your wheels
that would mar or leave residue on the board, such
as nails, glue, sticky notes, or tape.
Different types of Lego motors are available. You
may use up to two motors in your vehicle. Because
the motors are a shared resource, make them easy
to attach and remove from your vehicle.
You may not interact with the top of the board
(grappling hook or similar tool) or the outside world
(walls or sprinkler pipes). Your vehicle may interact
with the edge of the board.
Your teacher will make exceptions on a case-bycase basis.
10
Design Issues
Here are some items you should consider, design,
and calculate:
What are the different ways your vehicle could fail—
that is, stop climbing the slope? (Tip over, stall the
motor—not enough torque—or slide back down
the hill.)
How can you prevent each of these? Be specific.
What does this tell you about how you design the car?
(Where the mass is, whether you want big or small
wheels, how many gears to use, etc.)
Do you want to use the plain motors or the gear
motors (the funny-shaped ones)? Why?
Which wheels do you want to use? Why?
Are there other ways to increase and decrease quantities you care about (friction, normal force, mass, wheel
radius, gear ratio, etc.)? Which of these actually makes
a difference?
Presentation
Keep a log of your design ideas, your physics research
and testing, and the results of the modifications to your
vehicle. You’ll present your vehicle and demonstrate it
in class, and explain briefly how you optimized it.
(Adapted from Eric Smith, Ben Davis, and Alexis Cavic
of the Massachusetts Institute of Technology, who
originally developed this project)
11
EVALUAT I O N RUBRIC
Calculating Gradient: A Math Moment
Categories
0-1 point
2-3 points
4-5 points
0 to 20°
20 to 35°
More than 35°
Does not move or moves
backward or sideways
Moves forward, but
slowly or with significant
curvature
Moves forward swiftly and
climbs with relative ease
Plan provides clear measurements and labeling for most
components. Drawing is
clear, though scale may
be slightly inaccurate.
Plan is neat, with clear
measurements; labeling
and scale are correct for
all components.
Construction appears
careless or haphazard.
Many details need refinement for an efficient or
attractive car.
Fairly careful construction
and accurately followed
plans, but 2-3 details need
refinement for an attractive
and efficient product.
Great care taken in
construction; the car is neat,
attractive, and follows
plans accurately.
Scientific
Knowledge
Explanations by the majority of group members do not
illustrate much understanding of the scientific principles applied in the car’s
design and construction.
Explanations by the majority
of group members illustrate
mostly accurate understanding of the scientific principles applied in the car’s
design and construction.
Explanations by all the group
members illustrate clear and
complete understanding of
the scientific principles
applied in the car’s design and
construction.
Individual
Journal
Journal provides very little
detail about the process
of planning, constructing,
and testing the car. Does
not reflect group dynamics
and division of labor.
Journal provides much
detail about the process
of planning, constructing,
and testing the car, and
provides some reflection
on group dynamics and
division of labor.
Journal provides a
complete record about
the process of planning,
constructing, and testing
the car, including reflection
on strategies and reasons
for modifications and innovations. Clearly discusses
group dynamics and
division of labor.
Few entries made; they are
not dated or are too messy
to read.
Several entries made; most
are dated and legible.
Several entries made; all are
dated and legible.
Function
(Quantitative)
Function
(Motion)
Plan and Technical Plan shows inaccurate
measurements, is not
Drawing
to scale, or is drawn or
labeled inaccurately.
Construction
(Content)
Individual
Journal
(Appearance)
12
WEB SITES
http://www.nrel.gov/education/student/natjss.html
(This site has information about making model solar
cars, including rules for participation in the National
Junior Solar Sprint competition. Budget permitting
for solar cells, this activity is highly recommended
for your middle or high school classes.)
Teach e rs and students may find the following Web sites
i n fo rm ative while wo rking on the Classroom Challenge s .
http://www.howstuffworks.com (This Web site has hundreds of articles about how things work, including all
car parts. Look under the “transportation” category,
then “automotive.”)
http://www.tnris.state.tx.us/K-12/topolesson.html
(A great source for free topographic maps to use
in the activity on calculating gradient.)
http://www.pitsco.com (This company sells dragster
and other car kits at reasonable prices.)
http://www.nas.nasa.gov/About/Education/Racecar/
(A great site to learn about aerodynamics in race car
design)
To see Junkyard Wars on DiscoverySchool.com,
visit the Web site below.
http://school.discovery.com/networks/junkyardwars
(Interactive games and puzzles; ideas for challenges,
projects, and activities; and other teacher resources
support the Junkyard Wars Classroom Video Kits.)
http://www.highwaysafety.org/ (In the interest of getting students to drive safely—unlike some of the drivers in the Junkyard Wars episodes—this site shows the
results of crash tests, including pictures and ratings.)
13
Episode I: Jumbo Trucks
Name___________________
After Segment 1
A jumbo truck must be able to go over large bumps, including crushed cars. What materials will the teams search
for in the junkyard? Sketch a general design that shows where those materials will be used.
Look for evidence of teamwork during the video. Are conflicts resolved successfully?
The teams choose special tires for their trucks. What are the pros and cons for each type of tire? There is concern
about the skinny tires used by the Ghost Mountain Riders; how do the dual tires help to correct the situation?
Law Dawgs
Ghost Mountain Riders
What is the purpose of the truck’s suspension? How do the teams differ in designing their suspension?
After Segment 2
With three hours remaining, how have the teams’ plans changed because of materials or time limitations?
What are the problems you see with each team’s construction so far?
Continue to record instances where you see team members resolving conflicts or supporting each other’s work.
The hosts analyze the teams and their interactions, as well as their construction. Do you agree with their
descriptions? Give examples.
After Segment 3
In your opinion, which team has the best-built jumbo truck? Which team has the best overall design?
Give evidence to support your answers.
Predict which team will have the fastest truck. Give reasons for your choice.
Pay attention to the trucks as they move over the crushed cars; watch for the importance of the professional
driver’s pointers.
Record the times for each race, and circle the winning time below.
Race
Law Dawgs
Ghost Mountain Riders
1
2
3
Average
Calculate the average time for each team. If average times had been used, would the winner be the same?
14
Episode II: Climbing Car
Name___________________
After Segment 1
Compare the designs the experts developed. Sketch and describe each team’s basic design.
Look for evidence of teamwork during the video. Are conflicts resolved successfully?
How does each team try to manage the power-to-weight ratio for their climbing car?
After Segment 2
With five hours remaining, which team is further ahead in their construction?
How have the teams’ plans changed because of materials or time limitations?
Continue to record instances where you see team members resolving conflicts or exhibiting good communication
among themselves.
Why does the Pit Crew choose twin tires? What are the advantages of using them?
How do the teams make sure the driver is safe? Describe or sketch the designs chosen.
After Segment 3
In your opinion, which team has the best-built climbing car? Which team has the best overall design? Give
evidence to support your answers.
Predict which team you think will have the fastest car. Which team do you think will make it farther up the hill?
Give reasons for your choice.
The judge expresses concerns about each team’s vehicle. List some of his comments in the table below, then see
if his predictions become reality during the testing phase.
Pit Crew
Jet Jocks
Concerns
and Predictions
Testing Results
Describe in sentences the results for each team. What changes or repairs did each team have to make?
15