Research Experience for Teachers (2017-2018)
Electricity and Magnetism
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Pre/Post Test: Pre-Test Post-Test |
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Keywords:
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The Big Idea (including global relevance) Access to and control over electricity defines quality of life around the world, but many contexts deny individuals or groups access and control over the electricity they need. Not only do many parts of the world experience rolling blackouts due to weak electrical infrastructure, but global climate change is producing intensified storm events that temporarily damage the power grid. |
Essential Questions
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The Hook Before the Hook, as a warm-up, have students respond to a Google Question asking them how frequently they plug in their phones to charge them and a follow-up question asking them how long their phone will last without being recharged. The Hook: Show a brief video montage of blackouts, brownouts, and natural disasters interrupting power supplies (there are a number of good videos created in the wake of Hurricane Maria through Puerto Rico in September 2017). Initiate a discussion with students regarding how long before a power outage would be a problem. Crowdsource a list of electricity-driven devices that enable our current quality of life. Ensure inclusion of things like showers/baths, dishwashers, laundry machines, microwave ovens, cooktops, hair dryers, electric razors, cell phones, cars (electric starters, radios, etc.). |
The Challenge Mechanisms that transform a motor into a generator; can be hand-operated, foot-operated, bicycle-operated, wind-operated, etc. |
Guiding Questions
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ACS (Real world applications; career connections; societal impact)
Access to electricity is often a life-or-death proposition around the world; for students, it is typically merely a case of convenience or inconvenience.
knowing how to design and build a generator will not, in itself, impact society much. However, having an understanding of the way electricity works will enable the students to make smarter choices about the ways they use their electronic devices and the ways in which they relate to power supply and storage issues in general.
Cara Shapiro, a mechanical engineer and systems engineer at Ethicon, will be a guest speaker who will explain the various roles of people who must form a team to build endoscopic surgical devices. She will also explain why their devices use a proprietary generator instead of relying on electricity directly from the wall outlet.
Other related careers:
- Electrical engineer
- Mechanical engineer technologist
- Civil engineer (for large-scale generator builds)
- Construction management technologist (for large-scale generator builds
Misconceptions
- students did not imagine electricity as the movement of electrons from one atom to the next
- although students ultimately recalled that batteries rely on chemical reactions, they needed to be prompted to apply this knowledge in explaining how batteries store and release energy
- students imagined that batteries are recharged by packing electricity into them
- students have difficulty appreciating the presence of potential (pressure) on electrical current
Unit Lessons and Activities
- Lesson 1: Electricity
Students need to understand current, electrical potential, and resistance (Ohm’s law). They need to recognize basic circuit diagramming symbols and standards and they need to understand the difference between series and parallel circuits.- Activity 1: (CBL) Determine relevant Essential question and Challenge options (1 class period). In this activity, students are exposed to the context in which the challenge will have to be situated. Students are provided with an opportunity to shape the direction of the challenge, which will be pursued in Activities 3 and 4.
- Activity 2: Build D-Cell motors using copper wire, battery, magnets, and paperclips (2 class periods). During this activity, students will gain hands-on exposure to the physical operations of motors in a way that makes the role of coils and magnets visceral. This provides reinforcement of theoretical explanations of the interactions between electrical and magnetic fields.
- Lesson 2: Generators
Students need to understand the similarities between motors and generators and how they rely on magnetic fields to move electrons and how those moving electrons permit energy transfer to do work such as turning on a light or pushing a multimeter needle. Students need to be able to transfer their knowledge of mechanical advantage (which they learned in the pre-requisite STEM course) to complex machine design (instead of simple machine design, which they did in the previous class). Students also need to be able to communicate their work through a scripted video presentation that is edited to fit in a 60-second commercial slot.- Activity 3: (CBL + EDP) Design and build generator (15 class periods). During this activity, students will apply knowledge of mechanical advantage, electricity, and magnetism to produce a functional solution to a real-world problem. Through the EDP process, they will develop an array of viable options and each team will have to choose one of those strategies to pursue.
- Activity 4: Make a video marketing the generator design (5 class periods). In this activity, students will continue working on their second (or third) iteration of their generator designs and will begin putting together a short (60-second) Kickstarter-style video explaining how their device works and why it is a great solution for the problem of access to electricity. The narrative of their marketing strategy will in part depend on whether their solution focuses on a hand-held device, a wind-driven device, a bicycle-driven device, et cetera, since each type of solution will appeal to a slightly different group of consumers and/or use situations.
- Evidence of CBL: Activity 1, Activity 3
- Evidence of EDP: Activity 3
Additional Resources
Because Activities 3 and 4 are open-ended, CBL-style events, students will be making inventive use of class spaces and supplies, and will be permitted to upcycle materials from home to supplement the options already in the classroom. Because this is the second year these students have been in my classroom working with me, they may also think to request access to other supplies they know to be in the room (such as Legos, surgical tubing, a Web cam, acrylic paints, et cetera).