Lesson Plan Industry Sector
Engineering & Design

Modeling Resistance

Lesson Plan Overview / Details

Resistors in an electrical circuit are made of graphite and resin.  In this activity students will model resistors in an electrical circuit using graphite art pencils and graph paper.  Students will draw lines of graphite on the graph paper and measure the electrical resistance with a digital volt ohm meter (VOM). Students will discover the relationship between the length of the lines and the electrical resistance and the width of the lines and the electrical resistance.  These relationships are the basis for the equations that the students will use to calculate total resistance in a series and parallel circuit.

Lesson Time 2 Class Periods

Resistor Execution Introduction
10 Minutes
Instructions
10 Minutes
Modeling Activity
60 Minutes
Debrief/ Assessment
20 Minutes

Objectives and Goals

• Students will correctly measure the resistance of a graphite line with a VOM.
• Students will produce a graph of the relationship between the length of a graphite line and the resistance of that line.
• Students will produce a graph of the relationship between the width of a graphite line and the resistance of that line.

Activities in this Lesson

• Resistor Execution - Hooks / Set

Students will watch a video of a resistor plugged into an electrical outlet or watch their instructor demonstrate it live in front of class.

• Students will draw graphite lines on graph paper and then measure the electrical resistance of the lines.with a meter.

• The Electrical Resistivity of Graphite [ Download ] This document contains the directions for the modeling activity.

Assessment

Assessment Types:
Students Graphs

Students will submit their graphs showing the relationships between the dimensions of the graphite lines and the resistances. The instructor is looking for linear relationships (a straight line ) on the series graph and a Inverse relationship (a hyperbola) on the parallel graph.  The slopes of the lines are not significant because of the accuracy of the meter and the thickness of the lines.  The instructor should look for proper shapes in assigning grades.