Subject Area Lessons

## #2308. Intro to Ohm's Law

Science, level: Senior
Posted Sun Jul 8 12:20:18 PDT 2001 by Art Campbell (arthur_campbell@elanco.k12.pa.us).
Garden Spot High School, New Holland, PA
Materials Required: power supply, resistor, multimeter
Activity Time: 35 - 40 minutes periods
Concepts Taught: Simple circuits and Ohm's Law

1) The lesson will begin by passing around circuit boards and resistors for students to familiarize themselves with. Students will already have prior knowledge of resistors and how circuit boards work. As a quick review students will be required to find the value of the resistor using the color bands as well as with the multimeter. We will have a brief discussion about the meaning of current, voltage and resistance.
2)Students will set up the circuit and increase the voltage and measure the interval at which the current increases. This will be done for five different voltages. Therefore we will have five sets a data points. The students will make a graoh of voltage versus current. They may do this using software or by hand. The students will find the slope of the line and determine what physical quantity from the lab it represents.
3)The students will see that voltage and current are directly related. Therefore, the curve will be linear (a straight line). The slope of the curve will be the value of the total resistance in the ciruit. The equation of the line in terms of current (I), Voltage (V), and Resistance (R) will be V = IR. 