Physics

Ohm's Law

Lesson Plan

State Standards:

5.2 Interpret and apply Coulomb's law.
5.3 Explain the difference in concept between electric forces and electric fields.
5.5 Identify appropriate units of measurement for current, voltage, and resistance, and explain how they are measured.

Essential Question:

How do current, voltage, and resistance relate to one another?

Lesson Question:

How do current, voltage, and resistance relate to one another?

Introduction:

How do you light a light bulb? What is electricity? What is it that moves and gives the bulb energy? What is current, voltage, and resistance? If you add more batteries to a circuit what happens to a light bulb? If you add more light bulbs what happens? Why?

Task:

You job is to figure out how a circuit works - from the very basic to more complex relationships. First you will just try to light a bulb. Then you create and implement an investigation to uncover more properties of a circuit.

Lesson Experiences:

  1. Start with just one battery, one bulb and one wire. Try to see if you find two ways to get the bulb to light. Once you have successfully lit the bulb, draw detailed diagrams for each set-up. Then draw two diagrams for set-ups that did not light the bulb.
  2. Once you have successfully lit the bulb watch this video for some background information on circuits:

3. Use the PHET simulation to explore current voltage and resistance and the relationships between them.
Circuit Construction Kit (DC Only), Virtual Lab
Click to Run

4. Take a short quiz online.
5. You and your partner are going to design an activity to find the relationship between voltage and current. You will be given wires, bulbs, and batteries in class. At home you can continue the investigation using the PHET simulation below. You will also post their results to the class wiki and discuss your findings with one another.
6. Your last step is to write up your investigation and your findings in a lab report. See the rubric as a guide for writing your report:

Conclusion:

Ohm's Law is V = IR. In your own words, what does Ohm's law mean? What does it look like in a circuit? What can you change in a circuit and how will it affect the other parts?

Assessments:

-Students will receive 5 points for lighting the bulb (1 for lighting it and 1 for each diagram drawn)
-5 points for the zoho quiz
-20 points for the lab report

Resources:

Image Credit: Ohm's Triangle