Overview

Out of class, individual students draw a circuit diagram for a home appliance of their choice, calculating the current passing through the circuit when the device is in use. This work, along with photos of their home breaker box, the device, and its power rating, as well as a list of all the rooms or areas in their home that have breakers, are posted into an online collaborative platform.

In class, students are assigned to groups; each group is charged with a particular room in a hypothetical home. Within each group, students examine their teammates' posts, compare and contrast their ...

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Out of class, individual students draw a circuit diagram for a home appliance of their choice, calculating the current passing through the circuit when the device is in use. This work, along with photos of their home breaker box, the device, and its power rating, as well as a list of all the rooms or areas in their home that have breakers, are posted into an online collaborative platform.

In class, students are assigned to groups; each group is charged with a particular room in a hypothetical home. Within each group, students examine their teammates' posts, compare and contrast their devices' power ratings, and analyze each member's circuit. Students highlight errors and provide suggestions for improvement. Working in the collaborative platform, each group constructs a circuit for their hypothetical room, incorporating all the devices selected by each team member. They must calculate the circuit when all devices are functioning, keeping to a 20A limit by removing devices if necessary.

Finally, using the circuit work completed by each group, a circuit for the entire home is built as a class, and its consumption is calculated by the instructor. The class then discusses the total current and power used, and the manner in which an electrical meter determines power consumption.

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Objectives

The objective of this activity is to explore the concepts of current, power, and power rating in the context of household appliances. Students become familiar with electronic circuits like the ones found in their own home, and come to understand their limitations and recognize the need for breaker boxes to stop circuits if needed.

Context and requirements

Level Grade 12-U0
Discipline Physics
Course Electricity and Magnetism
Activity Content Circuits, current and power consumption, power rating
Technological Requirements An online collaborative platform is used, however students can instead complete the activity on paper or onto whiteboards.
Best Use Practice, Review

Author’s Notes

Benefits

I feel the benefits of this activity are that the students get to investigate everyday devices they use to develop core competencies of the course, and the active learning involved helps them explore these competencies in a very interactive and stimulating way.

Challenges

Challenges included the use of SMART Amp which has limitations in terms of zooming the canvas and manipulating or duplicating content. Finding ways for the students to really engage with each other in the pre-class online activity was also a challenge. Not all students will have access to their building’s breaker box (for example, those living in apartments). In these cases students should find a photo of a breaker box online.

Tips

My suggestions would be to make sure you practice the entire in-class activity beforehand to get the timing right and guide the students carefully. You want to be sure the students are given enough hints to proceed, but that you aren’t giving away the entire procedure, and that your students are given enough time to finish their circuits and do the calculations. Also, leading up to that in-class activity, communicate well with them online and remind them to bring a tablet or laptop if they can.

Activity Pedagogical Components

Data Collection

INDIVIDUALLY, students take a photo of a breaker box. They also take note of all the different rooms/areas that are listed on it. Next, they choose (a) one area/room and (b) one electrical device that would typically be plugged in there (e.g., for a kitchen, a toaster or blender). They then take a picture of said device and its corresponding “power rating” in their home.

Data Analysis

Students draw a simple circuit diagram with their device as the sole element apart from a 120 V power supply. They then calculate the current passing through the circuit when the device is in use with the power equation. Students log into an online collaborative forum and post photos of (a) their breaker box, (b) their electrical device, (c) the device’s corresponding “power rating” and (d) their circuit diagram/current calculation into a forum prepared for the project. Only one student per class can post any given device. Students also include a bulleted list of all the rooms/areas that have breakers (witin the breaker box).

Peer Review

Students are assigned to specific groups (corresponding to particular rooms in a hypothetical home). Once assigned to groups, students (a) read their teammates’ posts, (b) analyse teammate circuits and (c) compare and contrast device power ratings. Students can correct teammates’ work by posting a “REPLY” highlighting errors and suggested corrections.

Jigsaw

Groups of students log into an online collaborative platform. They are then directed to a designated space within a worksheet that is shared by the entire class. Within their designated space, each group constructs a circuit for their hypothetical room, incorportating (a) a 120 V power supply and (b) all the devices selected by each team member. Students then calculate the current the circuit uses when all devices are functioning. The current limit for a typical home wire is 20 A. Should any group’s total current exceed this value when all devices are turned on, team-members must determine the maximum number of devices that can be turned on at a given time, thus re-calculating the current their circuit uses.

Consolidation

As a class, a circuit for the entire home is built, combining the work completed by each group for the individual rooms. The total current and total power used, along with the manner in which an electrical meter determines power consumption, are then discussed as a class.

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