Title: How Much Electricity Do You Use Each Year
Level: Middle School
Time: 30 minutes
KERA Goals: 1.9; 2.13; 2.4

Objective:

Students will be able to relate the usage of common household appliances to coal usage.

Materials: Student Worksheet

Background Information:

In the United States, electricity can be created from many different sources.  More than 50% of the electricity we use is generated by burning coal.

CoalNuclearHydroNatural GasOilOther*
54.9%21.7%9.8%9.4%3.9%0.4%

* Includes Solar, Wind, Geothermal, etc.

Here are examples of how much coal is used each year by the Smith's (a family of four) to produce the electricity needed to operate various appliances.

Electric Applianceslbs. of coal
1.Water heater3,375
2. Range560
3.Television256
4.Iron48
5.Hairdryer20
6.Vacuum cleaner37
7.Clock14

Activity:

One ton of coal can produce 2,500 kilowatt hours (kwh) of electricity.  One ton equals 2,000 pounds (lbs.).

  1. If the Smith family uses all the appliances listed in the chart above, how much coal is used in one year?

  2. How much coal does each family member use in one year, if each member uses the same amount of coal?

  3. In one year, how many kilowatt hours of electricity are used by the Smith family if they use all the appliances?

  4. How many years would the Smith family have to use the range, to equal the amount of coal used by the water heater in one year?

  5. If the Smith family bought the television on September 1, how much coal did the television use for the remainder of the calendar year?

  6. The Smith family decided to purchase an additional iron.  How much coal is used by both irons in one year?

  7. During a five year period, one iron worked for all five years.  The second iron worked for three years.  During the fourth year, the second iron worked for eight months, and during the fifth year for two months.  How much coal was used by both irons during the five years?


Answers:

1. 4,310 lbs.2. 1,077 lbs.3. 5,262.50 lbs.4. 6 years
5. 85 lbs.6. 96 lbs.7. 424 lbs.

Provided by the Mineral Information Institute