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Using the Kill-A-Watt Meter in the Classroom

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**Note to Teachers**

**The following sections include lesson plans, worksheets and supplemental reading material dealing with AC electricity.** AC electricity is in some ways "more complicated" than DC electricity, but on the other hand, students are already very familiar with AC electrical lights and appliances because they use them every day at home and at school. Building on this familiarity can be an effective method of introducing new and more challenging topics.

The Kill-A-Watt Meter is inexpensive, very easy to use, and almost "foolproof".

Students really like being able to "**make measurements themselves**".

** Contents**

*Kill-A-Watt Meter - Supplemental Instructions** ** *

This is a one-page addition to the instruction sheet that comes with the meter.

*Using AC Electricity – A two-part Science Lesson for Grades 3 – 5** ** *

This section includes detailed lesson plans and worksheets specifically targeted for use with elementary school students.

*Lesson Plan Themes Using the Kill-A-Watt Power Meter** *

This section includes lesson plan suggestions, questions, and supplemental reading material for use with mid-school and high school students.

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**Overview for Teachers **

The Kill-A-Watt Power Meter is designed to make electrical measurements using standard 3-prong 120 VAC outlets such as those found in houses, offices, and schools. When the meter is plugged into a standard 120 VAC electrical outlet, a standard 120 VAC electrical appliance can be plugged into the outlet located on the front of the meter.

The meter is especially useful for monitoring and comparing how much electrical power and energy are used by different appliances. For example, you can easily display how much power is used by a compact fluorescent lamp (CFL) compared to a standard incandescent lamp rated for the same light output. You can also measure how much power some appliances use even when they're turned "OFF". Students will learn to make simple electrical measurements; become familiar with standard measurement units used in physics and engineering, and improve their understanding of important concepts like "energy", "power", and "efficiency".

** ****What can you measure with this meter?**

The Kill-A-Watt meter can be used to measure the following electrical parameters:

**Volts**: the electrical force or "pressure" present that "forces" electrons to move thru an appliance

**HZ**: Hertz: frequency or how many times the applied voltage cycles or changes direction each second

**Amps**: Amperes - electrical current: the # of electrons moving or "flowing" through the appliance

**Watts**: the electrical power (energy per second) being used by the appliance.

**KWH**: Kilowatt Hours – the total electrical energy used by the appliance since the meter was reset

**Hour**: the total time that electrical power has been applied to the meter since the meter was reset

(Note: only engineers & technicians care about the following two electrical parameters)

**VA**: the result of multiplying Volts and Amps. Different from Watts for some AC loads

**PF**: the ratio of measured Watts to VA. It will equal 1 for some AC loads, but not all.

**Using the Meter**

The meter can display only one electrical measurement at a time. You can select the measurement you want by pressing the labeled key. Three of the keys have double labels. You can alternate between the two labeled measurements by pressing the same key again. The meter display will highlight the measurement that you have selected.

When the meter is plugged into a standard 3-prong 120 VAC outlet it will measure Volts, frequency in Hertz, and Hours - the cumulative time in hours since electrical power was applied. The other electrical measurements will read zero (except for PF which will read 1) until a standard 120 VAC electrical appliance (load) such as a lamp or a computer or a TV is plugged into the 3-prong outlet on the front of the Kill-A-Watt meter. When the KAW meter is unplugged or when electrical power to the meter is switched off, the total Hour and KWH readings will be reset to zero. Be sure to record KWH readings before unplugging the KAW meter.

**Caution:**** ****The Kill-A-Watt meter is no more (or less) dangerous than any other 120 VAC electrical appliance.**** ****Be careful plugging in and unplugging the meter, and plugging in and unplugging the electrical appliance.**** ****Young children should not be allowed to perform these tasks. Do not use appliances with frayed or cracked power cords or loose/unreliable power switches.**** **

**Caution:**** ****If an appliance such as a lamp has a standard 2-prong AC plug, it can be safely plugged into the 3-prong outlet on the front of the meter.**** ****But don't use this meter with old-style 2-prong 120 VAC wall outlets, with extension cords connected to such wall outlets, or with 2-prong to 3-prong AC adapters.**** ****The meter will function properly in these cases, but a safety hazard could be created if you then plug a 3-prong AC appliance into the meter outlet.**** **

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**Goals:**

** **1) Introduce the units used for electrical measurements

2) Demonstrate electrical measurements using common appliances

3) Teach the concept of energy efficiency

4) Allow students to make measurements, keep records, and compare results

5) Explore the economic and environmental considerations of energy use

**Objectives:**

Students will:

1) Measure and graph energy output from an electrical appliance

2) Use the terms "Watts," "Volts," "Amps" and "kilowatt-hours"

3) Perform calculations using the results of their measurements

4) Discuss the possible economic and environmental impact of our future decisions about energy use

5) Inventory electrical use at school and at home and consider how to conserve energy

**Vocabulary for students**

electricity

energy

meter

Volt

Amp

DC/AC

load

Watt

kilowatt-hour

force

current

power

incandescent

compact fluorescent

appliance

efficiency

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(PDF 32 pages formatted for double-side printing)

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