A hands-on virtual lab using the PhET Ohm's Law simulation to investigate the relationships between voltage, current, and resistance. Students collect data, graph results, and use CER to explain their findings.
Claim: Resistance and current are inversely proportional at a constant voltage.
Evidence: Tripling resistance (200Ω to 600Ω) caused current to drop to 1/3 (22.5mA to 7.5mA).
Reasoning: Resistance is the "opposition" to flow. Since the push (voltage) is constant, adding more obstacles (resistance) reduces the rate of flow (current) proportionally.
1. Based on your graph, what is the relationship between Resistance and Current?
2. Look at Trial 1 (100 Ω) and Trial 2 (200 Ω). What happened to the Current when the Resistance doubled?
3. Calculate \( V = I \times R \) for Trials 3 and 6. (Note: \( 1 mA = 0.001 A \))
Trial 3 (300 Ω) Calculation:
Trial 6 (600 Ω) Calculation:
4. Describe the shape of the graph in Part B. Is it a straight line? Explain why this makes sense mathematically.
5. Claim, Evidence, Reasoning (CER): How does Resistance affect Current?
Claim Your Direct Answer
Evidence Numerical data from the table
Reasoning Explain using "Opposition to Flow"
Final Summary: Ohm's Law
Based on your lab findings, why is the equation V = I × R a powerful tool for electrical engineers? How can they use it to design circuits that are both safe and efficient?
Physics Lab // OHM-OD-V4.2 // 03-11-2026
2. Doubling Effect: The current was cut in half (from 45mA to 22.5mA).
3. V = IR Check: Both trials should yield approximately 4.5V (the constant voltage used in the sim).
4. Graph Shape: Non-linear curve (hyperbola). It is not a straight line because current is inversely proportional to resistance (\(I = V/R\)).
5. CER Sample Response:
"Resistance and Current have an inverse relationship. Our data showed that increasing the resistance from 100Ω to 1000Ω caused the current to drop from 45mA down to only 4.5mA. This occurs because resistance is the opposition to current; more resistance means it is harder for charge to flow, reducing the current."
Adjust Resistance (Ω) and record Current (mA).
Trial
Resistance (Ω)
Current (mA)
Trial
Resistance (Ω)
Current (mA)
1
100 Ω
5
500 Ω
2
200 Ω
6
600 Ω
3
300 Ω
7
800 Ω
4
400 Ω
8
1000 Ω
Graph B: Current vs. Resistance
50.0 —
43.75 —
37.5 —
31.25 —
25.0 —
18.75 —
12.5 —
6.25 —
0.0 —
|
0
|
125
|
250
|
375
|
500
|
625
|
750
|
875
|
1000
Current (mA)
Resistance (Ω)
Connect data points with a smooth curve.
Analysis Questions: Part B
1. Based on your graph, what is the relationship between Resistance and Current?
2. Look at Trial 1 (100 Ω) and Trial 2 (200 Ω). What happened to the Current when the Resistance doubled?
3. Calculate \( V = I \times R \) for Trials 3 and 6. (Note: \( 1 mA = 0.001 A \))
Trial 3 (300 Ω) Calculation:
Trial 6 (600 Ω) Calculation:
4. Describe the shape of the graph in Part B. Is it a straight line? Explain why this makes sense mathematically.
5. Claim, Evidence, Reasoning (CER): How does Resistance affect Current?
Claim Your Direct Answer
Evidence Numerical data from the table
Reasoning Explain using "Opposition to Flow"
Final Summary: Ohm's Law
Based on your lab findings, why is the equation V = I × R a powerful tool for electrical engineers? How can they use it to design circuits that are both safe and efficient?
Instruction: Plot points and connect them with a smooth, curved line.
Analysis Questions: Part B
1. Based on your graph, what is the relationship between Resistance and Current?
2. Look at Trial 1 (100 Ω) and Trial 2 (200 Ω). What happened to the Current when the Resistance doubled?
3. Calculate \( V = I \times R \) for Trials 3 and 6. (Note: \( 1 mA = 0.001 A \))
Trial 3 (400 Ω) Calculation:
Trial 6 (1000 Ω) Calculation:
4. Describe the shape of the graph in Part B. Is it a straight line? Explain why this makes sense based on the math.
5. Claim, Evidence, Reasoning (CER): How does Resistance affect Current?
Claim: Answer the question in one complete sentence.
Evidence: Use specific trials from your table (e.g., doubling resistance).
Reasoning: Explain the concept of "resistance" to the flow of charge.
Final Summary: Ohm's Law
The mathematical formula for Ohm's Law is: V = I × R
Based on your lab findings, why is this equation a powerful tool for electrical engineers? How can they use it to keep electronic devices from overheating or failing?
Physics Lab Series // Unit 4: Circuits // Ohmic Odyssey
1. Based on your graph, what is the relationship between Resistance and Current?
2. Look at Trial 1 (100 Ω) and Trial 2 (200 Ω). What happened to the Current when the Resistance doubled?
3. Calculate \( V = I \times R \) for Trials 3 and 6. (Note: \( 1 mA = 0.001 A \))
Trial 3 (300 Ω) Calculation:
Trial 6 (600 Ω) Calculation:
4. Describe the shape of the graph in Part B. Is it a straight line? Explain why this makes sense mathematically.
5. Claim, Evidence, Reasoning (CER): How does Resistance affect Current?
Claim
Evidence
Reasoning
Final Summary: Ohm's Law
Based on your lab findings, why is the equation V = I × R a powerful tool for electrical engineers? How can they use it to design circuits that are both safe and efficient?
Physics Lab // OHM-OD-V4.2 // 03-11-2026
1
100 Ω
5
500 Ω
2
200 Ω
6
600 Ω
3
300 Ω
7
800 Ω
4
400 Ω
8
1000 Ω
Graph B: Current vs. Resistance
50 — 40 — 30 — 20 — 10 — 0 —
|
0
|
200
|
400
|
600
|
800
|
1000
Current (mA)
Resistance (Ω)
Analysis Questions: Part B
1. Based on your graph, what is the relationship between Resistance and Current?
2. Look at Trial 1 (100 Ω) and Trial 2 (200 Ω). What happened to the Current when the Resistance doubled?
3. Calculate \( V = I \times R \) for Trials 3 and 6. (Note: \( 1 mA = 0.001 A \))
Trial 3 (300 Ω) Calculation:
Trial 6 (600 Ω) Calculation:
4. Describe the shape of the graph in Part B. Is it a straight line? Explain why this makes sense based on the math.
5. Claim, Evidence, Reasoning (CER): How does Resistance affect Current?
Claim One sentence answer
Evidence Refer to at least two trials (R, I)
Reasoning Explain why using the concept of opposition
Final Summary: Ohm's Law
The mathematical formula for Ohm's Law is: V = I × R
Based on your lab findings, why is this equation a powerful tool for electrical engineers? How can they use it to design circuits that are both safe and efficient?
1. Based on your graph, what is the relationship between Resistance and Current?
2. Look at Trial 1 (100 Ω) and Trial 2 (200 Ω). What happened to the Current when the Resistance doubled?
3. Calculate \( V = I \times R \) for Trials 3 and 6. (Note: \( 1 mA = 0.001 A \))
Trial 3 (300 Ω) Calculation:
Trial 6 (600 Ω) Calculation:
4. Describe the shape of the graph in Part B. Is it a straight line? Explain why this makes sense mathematically.
5. Claim, Evidence, Reasoning (CER): How does Resistance affect Current?
Claim
Evidence
Reasoning
Final Summary: Ohm's Law
Based on your lab findings, why is the equation V = I × R a powerful tool for electrical engineers? How can they use it to design circuits that are both safe and efficient?
1. Based on your graph, what is the relationship between Resistance and Current?
2. Look at Trial 1 (100 Ω) and Trial 2 (200 Ω). What happened to the Current when the Resistance doubled?
3. Calculate \( V = I \times R \) for Trials 3 and 6. (Note: \( 1 mA = 0.001 A \))
Trial 3 (300 Ω) Calculation:
Trial 6 (600 Ω) Calculation:
4. Describe the shape of the graph in Part B. Is it a straight line? Explain why this makes sense mathematically.
5. Claim, Evidence, Reasoning (CER): How does Resistance affect Current?
Claim Your direct answer
Evidence Numerical data from the table
Reasoning Connect evidence using "opposition to flow"
Final Summary: Ohm's Law
Based on your lab findings, why is the equation V = I × R a powerful tool for electrical engineers? How can they use it to design circuits that are both safe and efficient?
1. Based on your graph, what is the relationship between Resistance and Current?
2. Look at Trial 1 (100 Ω) and Trial 2 (200 Ω). What happened to the Current when the Resistance doubled?
3. Calculate \( V = I \times R \) for Trials 3 and 6. (Note: \( 1 mA = 0.001 A \))
Trial 3 (300 Ω) Calculation:
Trial 6 (600 Ω) Calculation:
4. Describe the shape of the graph in Part B. Is it a straight line? Explain why this makes sense mathematically.
5. Claim, Evidence, Reasoning (CER): How does Resistance affect Current?
Claim
Evidence
Reasoning
Final Summary: Ohm's Law
Based on your lab findings, why is the equation V = I × R a powerful tool for electrical engineers? How can they use it to design circuits that are both safe and efficient?
Physics Lab // OHM-OD-V4.2 // 03-11-2026
Trial
Resistance (Ω)
Current (mA)
Trial
Resistance (Ω)
Current (mA)
1
100 Ω
5
500 Ω
2
200 Ω
6
600 Ω
3
300 Ω
7
800 Ω
4
400 Ω
8
1000 Ω
Graph B: Current vs. Resistance
80 — 70 — 60 — 50 — 40 — 30 — 20 — 10 — 0 —
|
0
|
125
|
250
|
375
|
500
|
625
|
750
|
875
|
1000
Current (mA)
Resistance (Ω)
Connect data points with a smooth curve.
Analysis Questions: Part B
1. Based on your graph, what is the relationship between Resistance and Current?
2. Look at Trial 1 (100 Ω) and Trial 2 (200 Ω). What happened to the Current when the Resistance doubled?
3. Calculate \( V = I \times R \) for Trials 3 and 6. (Note: \( 1 mA = 0.001 A \))
Trial 3 (300 Ω) Calculation:
Trial 6 (600 Ω) Calculation:
4. Describe the shape of the graph in Part B. Is it a straight line? Explain why this makes sense mathematically.
5. Claim, Evidence, Reasoning (CER): How does Resistance affect Current?
Claim Your Direct Answer
Evidence Numerical data from the table
Reasoning Explain using "Opposition to Flow"
Final Summary: Ohm's Law
Based on your lab findings, why is the equation V = I × R a powerful tool for electrical engineers? How can they use it to design circuits that are both safe and efficient?
1. Based on your graph, what is the relationship between Resistance and Current?
2. Look at Trial 1 (100 Ω) and Trial 2 (200 Ω). What happened to the Current when the Resistance doubled?
3. Calculate \( V = I \times R \) for Trials 3 and 6. (Note: \( 1 mA = 0.001 A \))
Trial 3 (300 Ω) Calculation:
Trial 6 (600 Ω) Calculation:
4. Describe the shape of the graph in Part B. Is it a straight line? Explain why this makes sense mathematically.
5. Claim, Evidence, Reasoning (CER): How does Resistance affect Current?
Claim Your Direct Answer
Evidence Numerical data from the table
Reasoning Explain using "Opposition to Flow"
Final Summary: Ohm's Law
Based on your lab findings, why is the equation V = I × R a powerful tool for electrical engineers? How can they use it to design circuits that are both safe and efficient?
Connect your data points with a smooth, curved line of best fit.
Part B Synthesis: Resistance & Current
1. Based on Graph B, what is the mathematical relationship between Resistance and Current?
2. Explain why the line is curved rather than straight. Use the formula \( I = V / R \) in your explanation.
CER: How does Resistance affect Current?
Claim
Evidence
Reasoning
Final Summary: Ohm's Law
Based on your lab findings from both parts, why is the equation V = I × R a powerful tool for electrical engineers? How does it help them predict circuit behavior?
