Introduction: Ohm's Law: IntroductionWhat is Ohm's Law?
Ohms Law is a mathematical equation explaining the relationship between Voltage, Current, and Resistance within electrical circuits. It is defined as follows:
E = I x R
- E = Voltage (Voltage is an electric potential difference between two points on a conducting wire. Voltage is measured in volts and comes from various sources such as electric outlets and batteries.)
- I = Current (Current is measured in amps. Current is charged particles which flow from the voltage source through conductive material to a ground.
- R = Resistance (Resistance is the opposition that a material body offers to the passage of an electric current. Resistance is measured in ohms. Examples of items with resistance are light bulbs and coffeemakers.)
Lesson ActivitiesThe activity consists of using a nominal six-volt battery (made up of four nominal 1.5 volt dry cells connected in series) to:
- Drive current through a simple circuit element and measure and record the current through the element and the voltage across the element as the number of cells in the battery is varied from a single cell to four cells.
- Plot points on the graph that represent the voltages and currents recorded.
- Draw a "best fit" curve through the data points for the element tested.
- Repeat the process for two or three different resistor circuit elements.
- Compare the curves and make observations about the nature of the curves for each element.
Six teacher handouts are provided:
- Ohm's Law Information Sheet
- Step By Step Lesson Plan Guidelines
- Appendix 1: Materials Sourcing Suggestions
- Appendix 2: Continuity Tester Assembly Instructions
- Appendix 3: Alternate Single Cell Battery Holder Photos and Diagrams
- Appendix 4: Optional Insulators and Conductors Activity
Two student handouts are provided for advance review:
- Ohm's Law Information Sheet
- Step By Step Procedures
Resources/MaterialsSee attached student worksheets and teacher resource documents.
Alignment to Curriculum FrameworksCurriculum alignment sheet is included in
PDF.
CategoriesElectricity And Magnetism,
Energy,
Mathematical Applications,
Technology
Take Survey