Lesson Plan Three
Don Linstadt
Name of Lesson: Ohm's Law, Watt's Law and Solving Formulas.
Objective: To compare the performance of four AA size batteries: The Eveready Energizer, Eveready Classic, Duracell, and Walgreen's Heavy Duty. These batteries represent some of the most expensive, most advertised and least expensive readily available batteries. .
Classroom Activities: The teacher will prepare the class by doing several problems using Ohm's Law, Watt's Law and solving for formula values. The students will divide into four groups. Each group will connect a 10 ohm resistor across their 1.5 volt battery, and take voltage readings every 5 minutes. The data will be recorded in a separate table for each battery. Later, all data will be displayed on the same graph for comparison purposes. Use time for the horizontal axis, and voltage for the vertical axis.
Conditions: This activity will take one or two periods. Students may work in groups of six. Each person has a job during the experiment.
Materials: One battery of each type listed above, four 10 ohm, 5% 0.5 watt resistors, four multi-meters or whatever number is available from the science department, and graph paper.
Methods of Assessment: When any voltage reading has dropped to 70% of the initial reading, the experiment is terminated. This 70% reading means that now the battery is only supplying one-half of its original power to the resistor. What conclusion(s) can be reached based upon the results of this experiment? Do students seem to enjoy doing simple electrical circuit analysis? Have they discovered an application for their mathematics?
Modifications/Accommodations: The jobs to be distributed among the students are: take voltage readings, record the data in tables, doing mathematics calculations, and carefully plotting all the graphs..
Standards Addressed: The English/Language Arts Standards addressed include listening, observing and writing. The Mathematics Standards include mathematical reasoning, 2.5; applying algebraic techniques to model work problems, 15; and using formulas, tables and graph, 30.