Unit 4.3 Nature and machine: implementation of forces

By the end of this unit, students will be able to:

• Construct a model representing all types of plate boundaries and plate movement mechanics in order to examine and explain how movement along one plate boundary affects movement along other plate boundaries
  • Apply concepts from Unit 4.2 and this model to examine and explain the role of gravitational and buoyant forces in plate motion and how energy can be transferred through continental collision
• Identify different forces acting upon objects, where and how energy can be transferred through collision, in order to design and build a real machine (Rube Goldberg) that can transfer energy using forces

This is the final unit in which new concepts will be introduced to the students and is intended as an opportunity for the application of these concepts at both the large Earth scale (plate tectonics) and small classroom scale (Rube Goldberg machine). This unit is a critical building block toward our ultimate goal of understanding motions in a Rube-Goldberg Machine and similar obstacle-course challenges (this unit's motivating question). In addition, prior units that explained plate tectonics (Unit 3) are revisited and updated now that we have the terminology and mechanisms for forces and motion.

The materials in this unit should take about four hours of class time, plus an additional four hours if the Plate Tectonics Box Model Extension activity is also completed. Most of the lab exercises rely on small group work and are best suited to smaller classes or a lab meet-up outside of a traditional lecture room.

In this course, plate tectonics are implicitly or explicitly themes in all three main overarching units: Unit 2.5 about the Hunga Tonga Volcano's energy, Units 3.5 & 3.6 on density and layering, and this unit (Unit 4.3) on forces. Complete all of these parts so that your students can build a deep understanding by viewing this topic through a variety of different lenses.

Teaching Materials:

All Slides: Unit 4.3 All Slides v2 (PowerPoint 2007 (.pptx) 10.4MB Aug30 24)

Materials for Plate Tectonics Box Model Extension: Box (ideal is 8" x 8" x 10" – but this is a great recycling opportunity), Smart Fab craft fabric, packing tape, box cutters and scissors, markers and cardstock, and binder clips (optional). Instructors should create a working box model to demo for the students before class.

Materials for the Rube Goldberg machine (suggestions - you can use just about anything!): Cardboard tubes, PVC pipe, popsicle sticks, boxes, weights, marbles, toy cars, dominoes, balloons, tape, brads, pins, binder clips, clamps, ring stands, string, springs, rubber bands, small buckets, tap lights, pulleys, other odds and ends

Reflection Assignment: U4.3 Reflection Assignment and Rubric.docx (Microsoft Word 2007 (.docx) 69kB Jul12 24)

Sample Student Reflections (this is Reflection 13): Reflection Examples Redacted.pdf (Acrobat (PDF) 1.8MB Jul8 24)

The Lab(s) is/are assessed as a Science Journal, as always. Science Journal TIDeS Instructions (Microsoft Word 2007 (.docx) 2.9MB Aug30 24)

Instructor Copy:

Unit 4.3 Plate Tectonics Box Model - Instructory Copy -- educator-only file

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Other Materials: Computer and projector, white board or chalk board with markers/chalk.

Pre-Class Assignment(s):

Before Part 1: Complete Scientist Spotlight Sang-Mook Lee - spend a few additional minutes online learning more about him. Be prepared to share something surprising or interesting that you learned about him.

Before Part 3: Students should enter with the beginnings of a plan for how they will build their Rube Goldberg machines: What is the goal of your Rube Goldberg project (i.e., what simple task will your machine accomplish?) and how do you plan to incorporate all the required elements? We recommend integrating these questions into the course LMS or technology of your choice - it's important that the students have started thinking about this before class so they can be productive with their class time.

In Class, Part 1: Plate Tectonics Box Model Extension Lab (~180-210 min)

Introductions/Recap/Review/Discussion (30 min):

• Students read about Sang-Mook Lee before class. Ask the class to share something surprising or interesting that you learned about him.
• Class discussion: recall plate tectonics from Unit 3 - what was missing? In the previous unit, this concept was discussed only from the lens of density. Reminder: We now have Newton's Laws. You will discuss with your class how these apply to plate motions - implies a variety of forces at work for all plate interactions.
• Think-pair-share: students will annotate a plate tectonics cross-section sketch with their hypotheses of which forces are acting where and doing what. For example: slab pull/subduction (gravity or negative buoyancy), applied force (collision, orogenesis), lithospheric plates on asthenosphere (buoyancy), divergence (tension force), friction (resistance from asthenosphere/mantle on sinking slab), volcanism (buoyant force)

Lab - Plate Tectonics Box Model (~120 min).

• Show working box model to students - ask them to figure out how it works - hypothesize? These box models are driven by slab pull (gravitational force).
• Walk students through constructing their own box models (slides). They will document the engineering design and function as they go to make sure they know how what they are building relates to the function of the example model.
• Once they have built their models, students use them to demonstrate what happens at the plate margins as the plates are in motion.
• Students draw and describe the motions at each plate boundary type. They should also document how movement at one plate boundary results in movement at other plate boundaries. This is a great cause-effect moment.
• Reminder: As always, students complete their Science Journals during this lab.

Post-activity synthesis (~30 min):

• Observing the unobservable: most of what we know about plate tectonics is inferred. Show/introduce seismic tomography briefly and show images of plate boundaries (faster velocities clearly depict subducting slabs). There is a nice opportunity to connect waves (unit 2) and density (unit 3) with driving forces of plate motions here.
• Think-pair-share while looking at seismic tomography data:
  • 1. What can you infer from these seismic tomography images?
  • 2. Examine the three images and apply your understanding of waves, density, and plate tectonics to generate evidence-based explanations
• Think-pair-share: Show plate motion velocity vectors on a map of the US. Explain the pattern(s) you observe with the arrows shown and what that might imply (and Recall: acceleration is a change in velocity, caused by a force)
• Follow-up example from the think-pair-share: we can infer that the Farallon Plate disappeared from the images we've been looking at.

In Class, Part 2: Introduce the Rube Goldberg Challenge (15 min):

• Complete this right after Part 1 or at the end of Unit 4.2. Make sure to do it before the students come to class for Part 3.
• Watch the OK GO Rube Goldberg music video. Discussion questions (remember: the students have analyzed the motion of their vertical rocket launchers and should use the same techniques here):
  • 1. What forces and energy transfers can you observe taking place?
  • 2. How are Newton's Laws demonstrated throughout the video?
• Explain Rube Goldberg machines, "Mission Possible!" in the annual National Science Olympiad (which is a Rube Goldberg machine competition)
• Think-pair-share - students identify how Newton's Laws are integral to designing Rube Goldberg machines
• Lead to Rube Goldberg activity by watching one or two lower-budget Rube Goldberg example videos

In Class, Part 3: Rube Goldberg Design Challenge, (~240 min)

This is a 2-day affair. Day 1 is to plan and design, and test build; day 2 is build, test, revise, and revise.

Day 1 (90-120 min)

• After reviewing some examples to get the idea of the concept of Rube Goldberg machines, in small groups students should begin designing their own. They should think of a task the machine will execute as well as examine the various materials provided and figure out how they work and how they can be a chain-reaction connected together. They should try to have the machine use as many forces and do as many transfers of energy as possible while still completing the task. It will be important to test actions, in particular, cause-and-effect actions, throughout the process on day 1. The following is a basic list of how to proceed.
  • Decide on the "job" you want done. (Ex. book to fall over, toy car to start rolling, turn on a light, initiate domino fall, etc.)
  • Start thinking about the cause & effect pairs of how you will accomplish this while examining available materials. Since materials are to be shared, they should take inventory and make sure they stake claims on limited "must have" items.
  • Start building/engineering your machine, one step at a time. Lay out your materials and what makes sense where.
  • Before construction, draw diagrams of your plan annotated with how you expect it to work, what forces are at play, and where energy transfers will occur. Design plans should also include potential materials and predicted "trouble areas" to prioritize for testing trials.
  • Test as you build. See what parts work and which parts need to be tweaked.
• Materials (students can bring in more from home): Marbles, toy cars, tap lights, pulleys, string, rubber bands, popsicle sticks, binder clips, tape, pushpins, brads, balloons, small buckets, PVC and other bits of plastic piping, other odds and ends.
• End of day 1 should result in sketched and annotated plans for the machine, with various aspects tested.

Day 2 (full lab period, 90-120 min)

• Students should be ready to follow their design plans and continue testing and revising as they build the machine. Two full lab days are recommended to have sufficient time to conduct complete test runs with re-builds and be able to capture a video of the complete machine operation.
• Once students are satisfied with their final complete design and preliminary tests, they should make an annotated sketch of the final built machine, before doing the complete first run. 
• It may (should!) not work perfectly on the first try! Students should be prepared to capture video of it just in case, or, more likely, to go back and re-engineer a couple of places before their next complete test run. 
• Once the machine has passed its complete (or final) run, they should work in their groups to answer the following discussion questions:
  • Was your machine successful in completing its designated task? 
  • How well do you feel you utilized your understanding of forces to plan your machine?
  • How might you improve your machine if you had more time and/or if you had access to additional supplies?
  • How do position, velocity, and acceleration factor into designing a machine like this?
• Reminder: As always, students complete their Science Journals during this lab. Observations and Interpretations/Discussion are completed with the worksheet, so it is only the General Description/Introduction that students must add on top of completing the worksheet. 

Part 3, Follow-Up Class (60 min)

• In class, share out videos from the groups' Rube Goldberg machine final runs and each group briefly presents a "highlights reel" of their post-activity discussion questions.

Both of the labs in this module require materials that instructors may or may not have lying around. Nothing is particularly difficult to find but you should plan to spend some time accumulating supplies.

Plate Tectonic box tips & tricks:

• Mark the box where you want to cut in pencil first. Then think through how it will work, then commit with marker, think again, then cut.
• Cut "fabric" to be the width of the box and 3x the length of the box.
• Line the cuts in the box with packing tape for both easier sliding of fabric through slits and reinforcement.
• Use binder clips at the center of fabric in the divergent zone for weight to add resistance and easier to "reset" boundaries.
• Cut a "viewing window" into the side of the box to "see" the divergent and convergent (subduction) boundaries "in action".

Students complete another Scientist Spotlight in this unit. The goal of these is to showcase an array of scientists in fields relevant to the topics of the day, some from long ago and others young and active today, together representing a diversity of people who have all overcome some challenge in pursuit of their scientific passion.

Both labs should be completed as Science Journals. See full description and rubric here Science Journal Instructions v4 (Microsoft Word 2007 (.docx) 2.9MB Aug30 24).

As always, students complete End-Unit Reflection. Read either or both of Visionlearning's scientists and the scientific community and origins of plate tectonics. Reflection Prompt:

• You have been provided with two readings for this reflection. You may read either or both. The development of plate tectonic theory is a fantastic example of the practice of science at work in the field of geology. The scientific community reading includes example stories of several scientists throughout history and describes more "human" aspects of science, including mentoring and collaboration. The prompt is the same for either reading.
• Including examples from your experiences building and experimenting with models throughout this class, as well as your recent Rube Goldberg team challenge, reflect on the benefits of collaboration, chance, mistakes, revision, and creativity in the processes of science and engineering (problem-solving)?

The Plate Tectonics Box model is modified and adapted from Tanya Atwater's transform boundary model.

We find this smart Fab craft fabric to be useful for constructing the Plate Tectonics Box model.

Ge, Xiou, Jinjun Xiong, and Lav R. Varshney. "Computational Creativity for Valid Rube Goldberg Machines." 9th International Conference on Computational Creativity, ICCC 2018. Association for Computational Creativity (ACC), 2018.

Fun video examples of Rube Goldberg machines that others have made:

• OK GO music video
• The breakfast machine
• Passing salt
• Kid's dog-feeding machine
• College students' machines
• A Rube Goldberg machine made by students

There are a handful of references and resources that are relevant to plate tectonics and specific to the Hunga Tonga volcanic eruption in the References and Resources section of Unit 2.5: System Mapping.