Energy and Electricity

Grade Levels: 6 - 8

Objectives

• Students will gain an understanding of the terms "volt," "amp," "watt," "watt-hour," and "kilowatt-hour."
• Students will collect data about electricity consumption.
• Students will work with equations.
• Students will report findings to the class.

Materials

• Student Assignment Sheet
• Data Collection Sheet

Procedures

1. Come to class prepared with some data from appliances in your own home, or in the school. Use this information to create problems that can be solved with the equation W = V x A.
2. Explain the terms "volt," "amp," "watt," "watt-hour," and "kilowatt-hour." This is not for high-school physics, so the technical aspects of electricity need not be covered; students are simply told that electricity has strength, or power, that is measured in amps, and that it is "pushed" into their homes by a force that is measured in volts. The amount of work that electricity does is measured in watts, and the amount of work done in an hour is measured in watt-hours. One thousand watt-hours equals one kilowatt-hour. Consumers are charged for their electricity by the kilowatt-hour.
3. Introduce students to the equation W = V x A (watts = volts x amps), and work some problem examples on the board.

   Notes:
   It is assumed that students participating in this project have a basic understanding of equations and related sentences. In other words, they should know that:

   if	W = V x A
   then	V = W/A
   and	A = W/V

   This is important because they should be able to find data for any two variables and calculate an answer for the third (for a particular electrical appliance or tool). An additional hour should be provided if students need work on solving equations.

4. Give students the Student Assignment Sheet and the Data Collection Sheet and discuss proper ways of finding information about appliances, and recording it on the data sheet.
5. Show students how to calculate watt-hours per week, watt-hours per month, watt-hours per year, and kilowatt-hours.
6. Their assignment is to take the data sheets home and complete the required research for at least six appliances or tools.
7. Students should be required to find out how much one kilowatt-hour of electricity costs from the local utility company.
   They can obtain this information from a family electricity bill or from a phone call to the power company. A figure for cost per kilowatt-hour is necessary so students can calculate how expensive certain appliances or tools are to operate per day, week, month, or year.
8. After they have completed their assignments at home, have them use their research findings to discuss the energy consumption of various appliances.
9. A discussion about energy conservation and production would be an obvious addition to this hour's lesson.
10. Ask students how they would react if a situation arose in which electricity had to be rationed.
    • Which appliances or tools could they live without and which would be essential?
    • What electrical machines, other than household appliances, are crucial to the quality of our modern life?
11. At the end of the hour, students turn in their homework.

Extension Activities

• An additional hour may be needed if time is to be spent in class calculating how much it costs to operate each student's list of appliances and tools.
• The project can be expanded to include increased emphasis on the data that students bring in. For example, charts can be made to compare the amount of electricity consumed by certain appliances, or a composite "household" can be developed to illustrate electricity consumption throughout a home. There are many directions this project can go once basic data collection has been completed.

Excerpted from Science Projects.