The two quantities that we will be looking at are electrical resistance (Ω) and voltage (V). Form a hypothesis stating how you think current (I) will be affected by changes to either voltage (V) or resistance(Ω) in a simple circuit.
Overview
A basic electric circuit will be simulated, consisting of a power supply, ammeter, resistors, and wiring. Using this circuit simulation, students will do several sets of measurements and plot those data. First, while keeping the resistance constant, voltage will be varied and its effect on electric current measured with an ammeter. Students should collect enough different voltages so they can sketch a graph. The plots will suggest the relationship between current, voltage and resistance, and can be used to justify Ohm’s law.
Standards
Next Generation Science Standards
Computational Thinking in STEM
- Data Practices
- Analyzing Data
- Creating Data
- Modeling and Simulation Practices
- Using Computational Models to Find and Test Solutions
- Using Computational Models to Understand a Concept
Activities
- 1. Introduction
- 2. Introduction to SImulation
- 3. Varying Voltage
- 4. Current in a Wire
Student Directions and Resources
A basic electric circuit will be simulated, consisting of a power supply, ammeter, resistors, and wiring. Using this circuit simulation, students will do several sets of measurements and plot those data.
1. Introduction
Purpose: Using data collected from simulations, you will derive the mathematical relationship between voltage, current, and resistance for a simple circuit.
Research Question: What does the electric current in a simple resistor circuit depend on?
Procedures: The data you want consist of measurements of resistance, voltage and current, the “Big 3” of electricity.
Question 1.1
Question 1.2
In your own words explain the difference between current, voltage, and resistance in a circuit.
2. Introduction to SImulation
You can use this model to set up various types of electric circuits. The pieces of that circuit are found at the bottom section of the model. You are able to place wires, light bulbs, switches, resistors and ammeters. To add a component to your circuit you can select it from the toolbox and then click somewhere on circuit to add. To remove a component, select the “X” from the toolbox and then click on the component in the workspace that needs to be removed. The circles with the numbers in them shows the voltage (V) at that point in the circuit measured in volts. Ammeters measure the current (I) of the circuit at that point in amps (A).
Take 5 minutes to mess around with and get accustomed to the simulation that you will be using. Create a working circuit!
Procedures:
Question 2.1
Upload a screen shot of your working circuit.
Upload files that are less than 5MB in size.
| File | Delete |
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Upload files to the space allocated by your teacher.
Question 2.2
What do you think the blue moving charges represent?
Question 2.3
Describe what happens if you make a circuit with just wires and a battery?
Question 2.4
What are the basic parts needed to make a working circuit?
3. Varying Voltage
- Rebuild a simple circuit making sure to include contain a light bulb, ammeter, and a battery
- Once you have built the circuit, go ahead and click on the modify option in the toolbox. You will see a magnifying glass appear over the battery and you will have the ability to increase or decrease the voltage of the battery.
- Change the voltage to 10 and record the current in the correct place in the table provided for circuit 1.
Use the model to complete the 6 different circuits in the table below. Make sure that all components of the circuits are connected in series.
Question 3.1
What is the effect on the current (I) of the circuit when the voltage (V) is doubled? Make a claim (answer) and support it with evidence (reference to specific trials) and reasoning that explain why those specific trials support the claim.
Question 3.2
What is the effect on the current (I) of the circuit when the voltage (V) is tripled? Make a claim (answer) and support it with evidence (reference to specific trials) and reasoning that explain why those specific trials support the claim.
Question 3.3
What is the effect on the current (I) of the circuit when the resistance (Ω) is doubled? Make a claim (answer) and support it with evidence (reference to specific trials) and reasoning that explain why those specific trials support the claim.
Question 3.4
What is the effect on the current (I) of the circuit when the resistance (Ω) is tripled? Make a claim (answer) and support it with evidence (reference to specific trials) and reasoning that explain why those specific trials support the claim.
Question 3.5
Use this table or the interactive table below to collect your data. If you use this sketch table, use the text button to place numbers in the empty cells provided. Be careful with the eraser, because it will clear the whole table. To increase the font size choose one of the numbers that works best. (Either 10 or 15).
Note: Draw your sketch in the sketchpad below
Question 3.6
Fill in the table. If you are using the sketched data table instead, type the word "table" in the first cell.
Question 3.7
Use what you have learned so far to construct an equation showing the relationship between voltage (V), current (I), and resistance (Ω).
Note: Draw your sketch in the sketchpad below
4. Current in a Wire
Question 4.1
What do you believe the blue circles represent in the model?
Question 4.2
Describe 2 similarities and 2 differences between this model and the last one you used.
Question 4.3
What do you think causes resistance in circuit? Do you think it is possible to have zero resistance in a circuit? If so, how might this be useful in the real world?
Question 4.4
Based on your observations, what role might resistors have in electronic circuits? After all, resistors waste energy and increase your power bill…why use them?
Question 4.5
List 3 ways that you can decrease the current in the wire?
Question 4.6
List 3 ways that you can increase the current in the wire.
Question 4.7
Sketch the graph that shows the relationship between voltage and current.
Note: Draw your sketch in the sketchpad below
Question 4.8
Sketch the graph that shows the relationship between resistance and current.
Note: Draw your sketch in the sketchpad below
Question 4.9
Describe the motion of electrons through a circuit. Be sure to use the words current, resistance, and voltage.
