Pinball Machine – SCOPES Digital Fabrication

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Author

Teresa Sappington
Teresa Sappington
K-12 teacher

Summary

A 9th grade class can learn conceptual physics as students explore digital fabrication tools to design a pinball machine. When they laser cut their prototypes, students will gain an understanding of the applications of potential, kinetic and mechanical energy through simple and complex machines.

What You'll Need

Lesson Overview (for students):

All mechanical energy is classified as either kinetic or potential. As students explore digital fabrication tools to design a pinball machine, they will gain an understanding of the applications of potential, kinetic and mechanical energy through simple and complex machines. By end of lesson, students will be able to design and build a digital fabrication pinball machine that will use at least one form of energy.

Key Concepts 

Conceptual Physics (9th Grade)

Conceptual Physics presents concepts of the major themes of physics. There are two ways that beginning students of physics can understand the topic: (a) through mathematical models, and (b) through concepts. This course takes the latter approach. The concept of energy is often introduced in the very first unit of 9th grade Conceptual Physics. Energy is a critical concept across all science disciplines and as such serves as both a disciplinary core idea in multiple disciplines and a crosscutting concept. It is essential for explaining a wide range of phenomena, solving problems that occur in everyday life, and learning other science ideas. For these reasons, energy plays a central role in the high school science curriculum.

Instructional Design: Confirmation Inquiry Level 3

Key Vocabulary Words:

Work, Joule, Power, Energy, Lever, Pulley, Force, Motion, Mechanical Energy, Potential Energy, Elastic Potential Energy, Chemical Energy, Gravitational Potential Energy, Kinetic Energy, Work-Energy Theorem, Law of Conservation of Energy, Machines, Efficiency, Watt, Horsepower

Key Concepts:

Energy

  • Energy is defined as the capacity of a physical system to perform work.
  • The Law of Conservation of Energy states that energy can neither be created nor destroyed. If you think energy has ‘disappeared’, it has not has been converted to a different type of energy.
  • There are two types of mechanical energy: kinetic and potential. Kinetic energy is the energy of motion and potential energy is stored energy.
  • Energy can be stored. Stored mechanical energy can be seen in rubber bands that are stretched.
  • Energy can be converted. Stored energy can be converted to motion by releasing a spring or rubber band.

Forces and Motion

  • Force is a push or pull on an object which changes direction of speed of motion.
  • The flipper in the pinball machine changes the marbles’ speed and direction of motion.
  • The force of gravity accelerates the ball down the incline of the pinball machine.

Levers

  • A lever is a simple machine that makes work easier for use by decreasing the force required to do work.
  • Levers involve moving a load around a pivot using effort.
  • The effort needed to lift a load is decreased, however the distance is larger. In turn the load is larger while the distance moved is smaller.
  • A bell crank is a lever with two arms that have a common pivot at their junction.
  • The bell crank on your pinball machine transfer horizontal force to vertical force.

Key Formulas

WORK = FORCE (X) DISTANCE

(W) WORK is the amount of FORCE needed to move an object a certain distance. Calculate the force in Newtons. (N) Work is done only when FORCE causes a change in the motion of an object.

JOULE = A Unit of WORK

(J) 1 N (x) m = 1 J (N = Newton)

1 Kg (x) m2/s2 = 1 J (Kg = Kilograms)

You will use the formula for Newtons (N) (X) distance in meters (m) equals JOULES (J). You will convert your mass to a FORCE in Newtons (N), then move the mass a certain distance in meters. The answer to the problem will be in JOULES of energy

ENERGY = The ability to do WORK

(E) Energy is measured in Joules

Law of Conservation of Energy = Energy cannot be created nor destroyed. Energy is our potential to do some type of work. We use energy constantly.

GRAVITY = Force of attraction between the two bodies of matter due to their mass. The Earth exerts a force on you of 9.8 m/s2. This is a constant and always applies, except in space.

Materials:

  • Brads or bolts and nuts
  • Corrugated cardboard

 

  • Posterboard
  • File folder
  • Hot glue gun and sticks
  • Large popsicle sticks or paint stirrers
  • Marble
  • Push pins
  • Rubber bands
  • Skewers
  • Miscellaneous small toys and objects
  • Paintbrushes and paints (for decoration)

Digital Fabrication tools used:

  • Laser Cutter
  • Vinyl Cutter (for extension activities)
  • 2D Vector Graphic Software
  • Adhesive Vinyl (for extension activities)

Design Files: https://drive.google.com/open?id=0B3tPBZnliO7bX1Q4bWY2ckhHWjg

The Instructions

Step One: Teaching Phase: How will the teacher present the concept or skills to students?

  1. Show students examples of pinball machines by showing the following videos: https://www.youtube.com/watch?v=gnrrbKFWL3Q https://www.youtube.com/watch?v=jqwOaPYjKXI (min 11:57-end)
  2. After watching the video, discuss the motion of the flipper. The flipper transfers energy to the ball to keep the ball in motion. Discuss with students how pinball machines are controlled with electronics so the energy transfer is electrical to mechanical.
  3. Show that the transfer of energy in their cardboard pinball machine will be elastic to mechanical.
  4. Point out that the travel of the ball is interrupted by bouncing off obstacles. These obstacles make the play more interesting.
  5. Show that there is a launcher mechanism off camera that causes the ball to launch into the playing field. The launcher gives the ball the initial speed on the playing field.
  6. Discuss the rubric for the activity.

Step Two: Making the base (Time 30-60 minutes)

  1. Cut a rectangle out of corrugated cardboard to the desired size.
    This is usually 18-24 inches long and 13-16 inches wide.
  2. Cut some long strips of cardboard to make the 4 sides. These sides will keep the marble on the playing field.
  3. Glue the strips around the perimeter of the board.
  4. Add cardboard ramps, cardboard obstacles, or small toys around the board to create obstacles or rebound surfaces. Students can also make their pinball machine themed with vinyl decals if time, materials and equipment permit.
  5. Cut angled cardboard pieces to attach to the bottom of the base to provide an angle for the playing field. A fast board has about 12-15 degree slope. A slower board has about 5 degrees slope.
  6. The included design files have all of the necessary components for an 16 inch x 10 inch base with a 10 degree slope and is capable of being made on an Epilog Mini 24”x12” laser cutter common in many Fab Labs. The file may have to be modified to work with your local equipment.

Teacher Led Discussion: Gravitational potential energy depends on the height of an object above the ground. In the pinball machine a larger angle results in a larger gravitational potential energy therefore larger kinetic energy. Because KE = ½ mv2 higher kinetic energy translates to higher speed.

Step Three: Making the flippers (Approximately 30 minutes required)

Teacher Led Discussion: A bell crank mechanism transfers horizontal motion to vertical motion. Show student videos of bell crank mechanisms in motion.

  1. For the pinball machine, the short leg is attached to the push button from the side of the pinball machine. This is the horizontal motion. The long leg has vertical motion and bats the marble back onto the playing field. Essentially a bell crank mechanism is two levers attached at a stationary point.

    Basic Bell Crank 

  2. Make a single L-shaped flipper from cardboard. This is a basic bell crank mechanism. A good starting point is for the long part of the L to be 3 inches and the short part 2 inches.
  3. Drill a stationary pivot hole in the corner of the single layer flipper.
  4. Test the flipper shape, size, and placement of the pivot and push button points. Your goal is to have a small horizontal motion, with a small forcerequired and a fast vertical motion to give the ball more speed.
  5. Once you have decided on your design, build two final flippers by gluing 4 layers of cardboard together.
  6. Cover the front of the flipper with poster board to give the marble a good surface for bouncing. The included design file has the components for two sets of flippers and is capable of being made on an Epilog Mini 24”x12” laser cutter common in many Fab Labs. The file may have to be modified to work with your local equipment.

Step Four: Make Push Buttons (Approximately 15 minutes required)

  1. Cut small rectangles about three inches above the bottom edge of the box.
  2. Cut and glue long strips of cardboard to make the main part of the push button. (See diagram below)
  3. Make small squares off cardboard to glue on the end to make top of the push button. This will be the part that the player will use to activate the mechanism.
  4. Place the push buttons in the rectangular slots on the playing field (created in #1)

Step Five: Attaching the button to the flipper (5 minutes required)

  1. Attach push button to the flipper in the location determined in Activity 2. Use brads, bolts, or skewers that will allow the pushbutton and flipper to rotate. You will need to come up with a design to effectively attach the buttons to the flippers. The basic design is shown.
  2. Add rubber bands to flippers and buttons provide a return force. Play with the arrangement of the rubber bands to find the best return force and smoothest flipper motion.Teacher Led Discussion: The arrangement of the rubber bands is very important. When the button is pressed the rubber bands should be stretched. The work done in moving the button transfers energy to the rubber bands. That energy is then released when the button is released and the rubber bands pull the flipper mechanism back to its original position. Some of the energy is transferred to the marble on the playing field.
  3. Once you are satisfied with the arrangement of rubber bands, flipper, and buttons, permanently attach the flipper mechanism to the playing field with a bolt, skewer, or dowel through the stationary point.
  4. Glue cardboard strips to the playing field to provide guides for the push button.
  5. The included design files also incorporate push buttons.
  6. Measure distance between where the button attaches to the flipper and stationary pivot:                  
  7. Measure distance between where the marble hits the flipper and stationary pivot:                            
  8. Find the IMA which is the ratio of the two distances (6 divided by 7):                               

Step Six: Making a launcher (5 Minutes required)

Teacher Led Discussion: The most common launcher for a pinball machine is a spring system, as seen in the picture to the right1. A spring system is very similar to a rubber band system because they both convert elastic potential energy to kinetic energy. A spring system can be stretched or compressed to gain elastic potential energy; however, a rubber band system can only be stretched. In the following directions, students will create a rubber band launcher. In the rubber band launcher pulling the paddle does work on the launcher mechanism creating elastic potential energy. When the system is triggered, the elastic potential energy is converted to kinetic energy putting the ball into motion. Students can develop alternate ball launching mechanisms such as a gravity ramp launcher or spinner launcher.

Picture from www.Pinballdecals.com

  1. Fold out a file folder and roll it up to make a launching tube.
  2. Glue a circular cardboard piece, slightly smaller than the launching tube, to the end of a dowel rod, paint stirrer, large craft stick, pencil, or similar long cylinder.
  3. Place the plunger made in #2. Attach a rubber band from the top of the file folder tube to the plunger. To change the speed of marble launch, change the type of rubber band and placement of the rubber band on the plunger.
  4. Attach the launcher to the side of the pinball board.
  5. Cut a square hole in the side of the top of the cardboard base.
  6. Attach a flat piece of cardboard and a curved piece of cardboard to carry the ball from the launcher to the playing field.

Step Seven: Making a ball catcher (5 Minutes required)

  1. Cut a 3 inch long x 1 inch high slot in the bottom of the playing field for the ball catcher.
  2. Create a catcher box by gluing together a small rectangular box.
  3. Attach the box below the 3 inch slot.
  4. As an extension activity, have the students design and laser cut their own box for a ball catcher.

Placing obstacles on the playing field/decorating the pinball machine

  1. Choose objects to place on the playing field to make obstacles for the marble as it travels on the playing field.
  2. Carefully decide on the layout; make sure that the marble will not get stuck on an obstacle.
  3. Use hot glue to attach obstacles.
  4. Paint or decorate the pinball machine to match a theme if you have chosen one.

 

Step Eight: FINAL PRESENTATION

  1. Students present their pinball machines to the class.
  2. Students complete reflective memo for the (uploaded to folder)

Teacher Led Discussion: Teacher will discuss levers and inclined planes, which are two of the simple machines. In most cases simple machines are used to make our lives easier by requiring a smaller input force to get a larger output force. In the case of the flipper, we sacrifice the force advantage to gain a larger range of motion.

The inclined plane is the playing field of the pinball machine. By having an angle we increase the speed of the marble as it goes down the incline toward the flipper. This makes the game more exciting and challenging.

Standards

Next Generation Science Standards Understandings:

  • Energy cannot be created or destroyed, but only changed from one form into another.
  • Mechanical energy can be considered either to be kinetic energy, which is energy in motion, or potential energy, which depends on relative position.
  • Energy exists in many forms, and when these forms change, energy is conserved.

Next Generation Cross-Cutting Concepts :

  • Time, space, and energy phenomena can be observed at various scales using models to study systems that are too large or too small.
  • The total amount of energy and matter in closed systems is conserved.
  • Energy drives the cycling of matter within and between systems.
  • Proportional relationships (e.g. speed as the ratio of distance traveled to time taken) among different types of quantities provide information about the magnitude of properties and processes.

Common Core English Language Arts/Science & Technical Subjects Standards:

  • 9-10.3. Follow precisely a complex multistep procedure when carrying out experiments, taking measurements, or performing technical tasks, attending to special cases or exceptions defined in the text.
  • RST.9-10.4. Determine the meaning of symbols, key terms, and other domain-specific words and phrases as they are used in a specific scientific or technical context relevant to grades 9-10 texts and topics.
  • RST.9-10.5. Analyze the structure of the relationships among concepts in a text, including relationships among key terms (e.g., force, friction, reaction force, energy).
  • RST.9-10.8. Assess the extent to which the reasoning and evidence in a text support the author’s claim or a recommendation for solving a scientific or technical problem.
  • RST.9-10.9. Compare and contrast findings presented in a text to those from other sources (including their own experiments), noting when the findings support or contradict previous explanations or accounts.

Common Core Mathematics Standards:

  • HSN.Q.A.1: Use units as a way of understanding problems and to guide the solution of multi-step problems; choose and interpret units consistently in formulas; choose and interpret the scale and the origin in graphs and data displays.
  • HSN.Q.A.2.: Define appropriate quantities for the purpose of descriptive modeling.
  • HSN.Q.A.3: Choose a level of accuracy appropriate to limitations on measurements when reporting quantities.
  • HSN.CED.A.2: Create equations in two or more variables to represent relationship between quantities; graph equations on coordinate axes with labels and scales.

Digital Fabrication Competencies: I Can Statements

  • S.2) Safety: I can operate equipment in a Fab Lab following safety protocols.
  • (DP.2) Design Process: I can design something in a Fab Lab using a specific process under close instructor guidance.
  • (DP.3) Design Process: I can create analog models (e.g. sketches, small physical models, etc.) to facilitate a design process.
  • (DP.4) Design Process: I can record and share my ideas during a design process to document the learning process (e.g. journal writing, group reviews, etc.).
  • (DP.5) Design Process: I can work with a group to follow multiple common design process steps (e.g. defining the user, brainstorming, prototyping, iterating, etc.).
  • (CAD.2) Computer Aided Design: I can draw a basic design using 2D Vector graphics.
  • (CAD.6) Computer Aided Design: I can design a 3D component using 2D design software (e.g. press-fit or folded components).
  • (MO.2) Machine Operation: I can safely operate a digital fabrication machine under close observation of an instructor.
  • (F.3) Fabrication: I can modify pre-designed components and subsequently fabricate the components using one digital fabrication process.
  • (SC.1) Sustainability and Commerce: I use scrap and renewable resources like cardboard first, before using higher cost materials. I understand the cost of various raw materials in the Fab Lab.
  • (CT.2) Critical Thinking: I can identify the design problem, investigation, or challenge.
  • (Q.2) Questioning: I can formulate questions that reveal important aspects of design process including problems and challenges.
  • (PS.3) Proposed Solution: I can propose alternative solutions to a design problem through iterations and determine their utility through execution.

Differentiated Instruction

The teacher may incorporate accommodations/modifications of IEP such as extended time, oral presentation, and scaffold learning. Example is the used of QUIZLET Flashcard on Energy https://quizlet.com/31988791/conceptual-physics-chapter-9-energy-flash-cards/

Enrichment students can do self-directed learning using Khan Academy. Introduction to Work and Energy https://www.khanacademy.org/science/physics/work-and-energy/work-and-energy-tutorial/a/what-is-gravitati onal-potential-energy

Optional Next Generation Science Standards (Physics A) for enrichment students including:

  • Physics A: HS – PS2 – 1. Analyze data to support the claim that Newton’s second law of motion describes the mathematical relationship among the net force on a macroscopic object, its mass, and its acceleration.
  • HS – PS2 – 2. Use mathematical representations to support the claim that the total momentum of a system of objects is conserved when there is no net force on the system.
  • HS – PS2 – 2. Use mathematical representations to support the claim that the total momentum of a system of objects is conserved when there is no net force on the system.
  • HS – PS2 – 4. Use mathematical representations of Newton’s Law of Gravitation and Coulomb’s Law to describe and predict the gravitational and electrostatic forces between objects.
  • HS – PS3 – 1. Create a computational model to calculate the change in the energy of one component in a system when the change in energy of the other component(s) and energy flows in and out of the system are known.
  • HS – PS3 – 2. Develop and use models to illustrate that energy at the macroscopic scale can be accounted for as either motions of particles or energy stored in fields.
  • HS – PS3 – 3. Design, build, and refine a device that works within given constraints to convert one form of energy into another form of energy.

Instructional Time: At least 2 hours are required for this lesson. However, time could vary significantly depending on the equipment available in your classroom and capabilities of the students.

Classroom Reading Material

Conceptual Physics Textbook. Chapter 9 (Energy-Teacher Version)
http://www.athenscsd.org/userfiles/55/Classes/790/userfiles/55/my%20files/ch9-energy-cp.pdf?id=5101

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  1. SCOPES-DF March 8, 2019
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