Rover Races & Tractor Pulls Engineering Design – Build Challenge


As we look forward to humans returning to the Moon for further exploration and on to Mars, we will need a means to move crew and materials on the surface of the planet. This will necessitate the design of rovers that are capable of performing in a wide variety of terrain and harsh environmental conditions. They must also be as light as possible since they must be launched to the planet on a rocket.

Students will be challenged to design and construct a rover and/or tractor to compete in traversing a race course by their vehicle. Through the challenge they will be expected to test and modify their prototype to improve its performance.

This lesson is an extension of the “Invent a Self-Driving Vehicle” challenge from the STEAM Student Set.

OBJECTIVES:
Through this lesson, students will engage in an engineering challenge that will require them to work collaboratively to design and build a solution to a problem.

Students will construct a rover and/or tractor to compete in traversing a race course by their vehicle. Explicit challenges will be given to students including distance, speed, terrain to be traversed or load to be pulled.

Students will gain an understanding of the reiterative process of design, build, test, modify. They will be asked to evaluate each trial and make modifications to their prototype to improve performance. The variables that might affect performance will need to identified and isolated to determine which contribute to the success of their vehicle.

ASSESSMENT STRATEGIES
– Are all students engaged?
– Are they sharing what they have learned about the littleBits modules with each other? If not, consider asking students to share one thing they have learned about the littleBits modules with the students in his/her group.
– Consider asking students to share something they tried that didn’t work and why.
– Students will journal in their Invention Log at the end of each phase, sharing their insights and questions, successes and challenges.
– How were students able to demonstrate their mastery of the lesson objectives through their use of littleBits?

DURATION:
Time Budget (minimum recommended)

– Introductory free exploration: 30 min
– Planning & first prototype:1-2 class periods of 45 – 60 min each
– Competition heats:1-3 class periods of 45 – 60 min each
– Teams are given 10 minutes between competition heats to make revisions to their prototype.

PREQUISITE KNOWLEDGE

Students should be able to construct simple circuits using the littleBits. They should have a familiarity with input and output Bits, the order in which they need to be connected, and their functionality. To accomplish this, students should have at least 30 minutes of time to explore the Bits before being issued the design challenge.

At culmination of initial exploration, students should be able to identify each Bit as an input or output and its function. They should be able to construct a simple circuit of power + input + output to meet a specific challenge; e.g. Make something that lights up, …makes a sound, …moves.

STANDARDS

Common Core Standards Alignment
– CCSS.ELA-LITERACY.CCRA.SL.1, SL.2, .SL.4
– CCSS.ELA-LITERACY.W.5.1.A, W.5.1.B, W.5.1.C, W.5.2, W.5.2.B, W.5.2.C, W.5.2.D, W.5.2.E, W.5.3, W.5.3.C, W.5.3.D, W.5.3.E, W.5.4, W.5.7, W.5.8, W.5.10
– CCSS.ELA-LITERACY.RST.6-8.3

Next Generation Science Standards Alignment for Elementary and Middle School:

Core Idea ETS1: Engineering Design
– 3-5 ETS1.A: Defining and Delimiting an Engineering Problem
– ETS1.B: Developing Possible Solutions
– ETS1.C: Optimizing the Design Solution

Core Idea ETS2: Links Among Engineering, Technology, Science, and Society
– ETS2.A: Interdependence of Science, Engineering, and Technology
– ETS2.B: Influence of Engineering, Technology, and Science on Society and the Natural World

KEY VOCABULARY

_ input _output _circuit _sensor _interactivity _system

_logic _structure _design _prototype _engineering _traction

_friction _torque _counterbalance _mass

HELPFUL LINKS

littleBits Invention Log

Examples of student solutions to the Rover Race and Tractor Pull Challenge

Google+ Hangout: littleBits Rover Races & Tractor Pulls

Note: Author recommends not showing students prototypes that have already been built as it tends to contaminate their initial design process. After they have completed at least one build-test-modify cycle, teachers may elect to share photos or videos of previous solutions to the challenge.

INSPIRATIONAL LINKS

Rover Races – show videos of lunar rover challenge:

Apollo 16 Lunar Rover

NASA Great Moonbuggy Race

LunarXPrize Rovers

Tractor Pulls- show videos of Iowa State Fair Tractor Pulls:

Tractor Pull highlights

Micro-mini tractor pull

Duration: 4-6 hrs

GRADE LEVEL
High School (ages 14-17)
Elementary (ages 8-10)
Middle School (ages 11-13)

DIFFICULTY
Advanced
Intermediate

SUBJECT
Engineering
Math
Physical Science
Social Studies
Robotics
Technology
Earth & Space Science

MODULES & ACCESSORIES USED (13)
branch (1)
dc motor (2)
power (2)
fork (1)
motorMate (2)
mounting boards (2)
remote trigger (1)
wheel (2)

OTHER MATERIALS USED (4)
variety of objects that could be used for wheels 1
250-1000ml plastic bottles 1
1’x8′ sheet of plywood (for tractor pull track) 1
variety of masses for tractor pull weight sled (10-500g) 1

LESSON GUIDE

STEP 1 : SETUP

This lesson is designed to be completed by students working in small groups of 2-4 students. The teacher could opt to execute the lesson with students working individually. Each group will need at least one STEAM Student Set and additional bits listed above (optional: +2 wires and IR trigger), plus one Invention Log per student. We suggest handing out the Bits after the introduction to keep students focused on initial instructions and review activities. For more experienced users, you may want to provide access to additional Bits to provide a greater diversity of circuit combinations. Place a variety of construction materials and tools in a central location in the room (see materials section above).

Teacher/leader will need to prepare the race course. For tractor pulls a standard “track” is used, constructed from a 8 foot x 1 foot sheet of plywood. The track is inclined 6 inches to create a 6% grade. A weight sled will also need to be constructed that can be mated to the tractor. The sled will need a hopper into which masses can be added during competition. A collection of masses to create loads from 100g to 500g. For rover races, the course should be 4 meters long with a terrain transition; e.g. hard floor to carpet.

STEP 2 : CONNECT

Introduce the challenge: Your teams are being asked to develop a rover or tractor for use on the Moon or Mars. The vehicles must be as lightweight as possible, yet functional. Rovers will need to be able to drive a course that traverses different surfaces (such as sand, carpet, tile or wood floors, etc.) as quickly as possible. Tractors will be judged by how much mass they can pull and how far they can pull that mass.

Based on the comfort level of the teacher and students, both vehicles could be developed concurrently, with students choosing which challenge to focus on first. The teacher could also simply choose which challenge he/she would like students to engage in. Another option would be to have all students first complete the Rover Races challenge and then move on to the Tractor Pull challenge.

Introduce the challenge by showing students video clips of full-scale competitions (see inspirational links above). What are the problems/challenges that will need to be solved to be successful in this project?

Students might identify: -speed -maneuverability -negotiating different terrain -pulling power -durability -payload capacity -mass of vehicle -physical size of vehicle

STEP 3 : TEACH

Design questions to explore. Discuss hypotheses to the questions below (or create your own) as a class, in small groups, and/or as a Invention Log writing prompt. Students will be expected to supply data and answers to these questions in their conclusions.

-Does size of wheel used make a difference? Consider: Tread width & Wheel diameter

-Are drive wheels better in the back, front or middle?

-Is a wide or narrow wheel base better?

-Is a short or long wheel base better?

-Does the mass of the tractor/rover matter?

-Is two-wheel drive (2WD) or four-wheel drive (4WD) better?

-Is it better to collaborate or work independently?

-Does the size of rubber band used matter?

-Is tractor drive better than wheels?

-Is it better for the wheels to all match in size?

STEP 4 : ENGAGE

Teams will be given time to explore the Bits for the challenge and brainstorm how these could be used to construct a vehicle. Students should record notes in their Invention Logs.

Teams will choose which vehicle, tractor or rover, they intend to build and create their first design. Build and test the prototype.

STEP 5 : PRACTICE

Teams compete with other teams to test their prototypes.

The IR Trigger modules are used as “starters” to ensure fair, hands-off starts. Use any IR remote control to trigger the circuit. (Note: If IR triggers are not available to your students, cars can be powered on and held at the start line until instructed to release.)

Rover Races Data Collection: Time how long it takes each rover to complete the course. Chart each iteration to evaluate the effectiveness of design modifications. More advanced mathematics students could calculate the rover weight to speed ratio to evaluate the effectiveness of designs.

Tractor Pull Data Collection: For each trial, students should record the mass and the distance pulled. The first heat of the Tractor Pull should have 100-200g of mass in the sled. Add 25g of mass to the sled with each subsequent heat.

After each heat, teams are given “pit time” to revise prototypes for second heats. (Repeat cycle of race, pit, race, at least once to provide opportunity for designs to evolve and be refined to meet the specific challenges presented by the course.)

STEP 6 : CLOSE

Invention Log entries, along with the data collected will be used to support a written conclusion/analysis of the effectiveness of the team’s prototype. Also included will be ideas for further revision.

Consider having the students share their projects with each other, explaining how the littleBits modules work together in their respective projects and how design choices contributed the the success of the prototype.

For a final discussion, consider asking students how littleBits assisted them in achieving the learning objectives of the lesson.

Make sure to encourage students to use academic language during this discussion.

STEP 7 : EXTENSIONS

Based upon this experience, think of how can you use littleBits to extend other lesson plans.

Consider introducing more sophisticated Bits in future lessons (e.g. logic gate or sensor modules).

Try having students explore more challenging principles/concepts using littleBits in future lessons.