Introduction
Definitions
Related work
AR as a tool for education
Cognitive assessment using Q-matrix theory
Modeling
Preparing an incidence Q-matrix
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Microskill 1 (MS1): Ability to understand current flow.
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Microskill 2 (MS2): Ability to understand polarity.
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Microskill 3 (MS3): Ability to understand circuit connections.
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Step 1 (S1): Connect two resistors in series.
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Step 2 (S2): Connect LED to resistors.
Validating the Q-matrix
Students’ knowledge space generated from the Q-matrix
Design microskills in an AR environment
The tasks
Electrical circuitry
Microskills | Learning Outcomes |
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Ability to understand current flow | Understand the circular path of electrons around a circuit Understand the difference between an open circuit and a closed circuit |
Ability to understand polarity | Learn to connect components in which current flows in one direction Learn to read polarized components, e.g., the positive (longer) leg of an LED needs to be connected to the positive terminal of the battery. Other components with polarity: capacitors, batteries, power supplies, transistors, voltage regulators |
Ability to understand resistance | Understand the opposition of a component to the flow of electric current Learn that electricity always follows the path of least resistance to ground (beware of short circuit) |
Ability to understand connections | Understand the connections between one component and another, with emphasis on the terminal ends of conductivity Learn that every component must be well connected to power the circuit (e.g., battery, bulb, and wires) |
Ability to recognize components | Learn to recognize 3–5 components and their functionality from memory Learn to read the shape and terminals of each component |
Ability to understand breadboard logic | Learn to understand the governing principles of breadboard connections and parts of the breadboard Understand how components may be inserted into the breadboard and how to connect them to each other |
Ability to understand series circuits | Learn to connect components in series, in which the current only follows one path Understand that series components are connected to follow a single path, without being separated by any branches (e.g., a string of LEDs) |
Ability to understand parallel circuits | Learn to connect components in parallel, in which the current is divided into two or more paths before recombining to close the circuit loop. The voltage across every component in the circuit is similar Understand that for two components to be connected in parallel, both ends of each component (e.g., LEDs) must be connected together |
Ability to read specs sheet | Learn to read the tables or descriptions that explain the terminals and connections of each component Understand the diagrams which will be overlaid on the component (e.g. do not use an input only terminal from a component if you require an output) |
Ability to read resistor color code | Learn to read resistor values from left to right towards the golden band Consult the color value chart to learn the resistor values from the first two colors, the multiplier from the third, and the tolerance from the fourth (golden) |
Steps | A | B | C | D | E | F | G | H | I | J |
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Microskills | ||||||||||
MS1: Ability to understand current flow | 0 | 0 | 0 | 1 | 1 | 1 | 1 | 1 | 1 | 1 |
MS2: Ability to understand polarity | 0 | 0 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 |
MS3: Ability to understand resistance | 0 | 0 | 0 | 0 | 1 | 1 | 0 | 0 | 0 | 0 |
MS4: Ability to understand connections | 0 | 0 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 |
MS5: Ability to recognize components | 1 | 1 | 1 | 1 | 1 | 0 | 0 | 0 | 0 | 0 |
MS6: Ability to understand breadboard logic | 0 | 1 | 0 | 1 | 0 | 0 | 0 | 0 | 1 | 1 |
MS7: Ability to understand series circuits | 0 | 0 | 0 | 1 | 1 | 0 | 0 | 1 | 1 | 0 |
MS8: Ability to understand parallel circuits | 0 | 0 | 0 | 1 | 1 | 0 | 0 | 0 | 0 | 0 |
MS9: Ability to read specs sheet | 0 | 0 | 1 | 0 | 0 | 0 | 1 | 1 | 1 | 0 |
MS10: Ability to read resistor color code | 0 | 0 | 0 | 0 | 1 | 1 | 0 | 0 | 0 | 0 |
Meta-steps
Study
Results
Keeping score during the tasks
Assessment by microskill
Think-aloud understanding of circuitry
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R1: Do you have a sense of what your closed circuit will look like? What will happen?
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P9: At the end of the circuit? I’m going to connect it to the < ultrasonic distance > sensor, and if all is well then the light is going to turn on (inserts resistor into the breadboard) R1: Yes, that’s the idea. Do you have a sense of why you are using a resistor in your circuit?
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P9: To try to lessen the electricity that goes to the light, to avoid breaking the light (points to LED in breadboard).
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R1: Do you have a sense of what the ends of the LED are telling you?
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P9: Smaller part is the cathode and the longer part is the positive part. R1: Do you have an idea of how to connect your sensor to the board?
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P9: Not too much, but I have to try to have the electricity go through all the board. I’m just not sure how to connect it, I guess (participant proceeds to multiple trials to connect the circuit).
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R1: Is your circuit closed? Why?
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P9: I don’t know…This is it? (participant hands it over to researcher).
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R1: So do you have a sense of how a closed circuit looks like?
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P15: I have to go from positive charge to a negative charge. So I always know that I have to go from the power to the ground and everything has to be connected so that it will light up the LED…(explains her circuit in much greater detail).
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R1: Do you know why we were using the resistor in the circuits? (points to the resistor in the board).
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P15: So I know that < the resistor > controls the current, so, like, it would make sense to regulate how much current gets through and not break the LED. (points to the current going from ESP32 to resistor to LED).
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R1: Do you know what the LED having a long side and a short side mean?
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P15: Yeah, this shows the polarized sides, so that the long side shows the positive side and the negative side goes to ground–negative side goes to ground, positive side goes to power or load (holds ends of the LED and spreads them with hand).
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R1: How do you check that your circuit is done? (no load is applied yet).
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P15: I would make sure that if I have a sensor—like the color < sensor > —, have to make sure it goes to the pins, and so like, these pins < from sensor > go to these pins of the ESP32, then the ground or the power from that sensor is on the board for the positive and negative charge, and then I make sure that the LED starts from the resistor. So I make sure that everything has current. I think of it as a circle that I need to close. (points to all components in breadboard one by one).