Title: How Much Does It Cost To Light Your School
Level: Middle School
Time: 90 minutes
KERA Goals: 1.12; 1.3; 1.6; 2.1

Activity Duration:

1 to 2 class periods, with assignments.

Objective:

The students will compute the cost of electricity used to light their classroom and their school for one hour through one year, the number of kilowatt hours of electricity used, and the number of tons of coal mined and burned to produce the electricity used.

Curriculum Skills/Processes:

Observing, collecting data, computing, organizing, and discussing.

Background Information:

Coal produces more than half of the electricity used in the United States, and is our most abundant domestic nonrenewable energy source.

More than 75% of the coal mined in the United States is used to produce electricity.  Typically it takes about one ton of coal to produce 2500 kilowatt-hours of electricity.  By checking the number of kilowatt-hours used during a billing period, a customer can determine how many pounds (lbs.) of coal were used to meet his or her needs-- presuming that all the power was coal-generated, of course.

Here are some examples of how much coal is used yearly by a family of four to produce the electricity needed to operate various appliances:

Electric Appliancelbs. of coal
1.Water heater3,375
2. Stove/oven560
3.Television256
4.Iron48
5.Hairdryer20
6.Vacuum cleaner37
7.Clock14

The U.S. has approximately 30% of the world's coal reserves.  Most of the costs of mining and burning coal in an environmentally safe manner are included in the cost of today's electricity. Consequently coal should remain a reasonably priced source of electricity compared to other sources (oil, gas, nuclear power).   The cost of transportation to deliver coal to the power plant can be the largest influence in the price people pay for electricity.

Materials:

Activity:

Have the students do the calculation listed in the activity and fill out the chart provided.  Discuss the actual cost per hour to operate a florescent bulb in your area and the reasons that regional electrical costs vary.

  1. First determine how much electrical energy it takes to light your classroom for 1 hour, then compute the cost.  Record this amount on the table below.

    Number of tubes in your classroom x 3 = Cost per hour to light your classroom

    *Note-- Fluorescent tubes cost approximately 3 per hour for the electricity needed to light them.  The cost ranges from 2  to 4.5 per hour, depending on where you live.

  2. Then, compute how much it costs to light your classroom for 1 day.  Record below.

    Cost per hour to light your classroom x Hours per day classroom is lit = Cost per day

Classroom

School

Cost per hour
Cost per day
Cost per week
Cost per month
Cost per year
Kilowatt hours used
Tons of coal used

Discussion:

  1. How much does it cost to light your classroom for 1 week? 1 month? 1 year?  How many kilowatt hours (kwh) of electricity were used?

  2. How many fluorescent tubes are there in your school?  How many classrooms?   How much does it cost to light your entire school for 1 hour?  1 day? 1 week? 1month? 1 year?  How many kwh of electricity were used?  Record your calculations below.

  3. An average 2500 kwh of electricity are produced by burning 1 ton of coal.  How many tons of coal would it take to light your classroom?  Your school?

  4. Discuss how you could "lower" the cost of lighting your classroom and your school?

  5. Why is coal a good fuel source for producing electricity?

  6. What are some of the problems we need to solve to make coal a better fuel source?

Provided by the Mineral Information Institute.