How much energy & money do LED lamps save?

Grade level: 4th – 5th grades

Skills: Multiplication

Related environmental issues: Energy conservation

The table below shows how much electricity each light bulb uses to light your room in 1 year.

Screen Shot 2018-11-03 at 9.18.30 AM

  1. Your house has 30 light fixtures.  How much electricity do you use during a year if you use a regular light bulb for each light fixture?
  2. How much electricity do you use during a year if you use an energy saving light bulb for each house’s light fixture?
  3. How much electricity can you save if you replace all of the 30 regular light bulbs with energy saving light bulbs?
  4. The average price of 1kwh-electricity in California was 21 cents in August 2018. How much money could your family save for electricity in a year if you replaced all of the 30 light bulbs with energy saving light bulbs in a year?




Answer keys

  1. 200 x 30 = 6,000 (kWh)
  2. 30 x 30 = 900 (kWh)
  3. 6,000 – 900 = 5,100 (kWh)
  4. 5,100 x 21 = 107,100 (cents) = $ 1,071


Which car is clearer – Ford F150, Toyota RAV4 or Honda Civic?

Grade level:  5th grades

Skills:  Multiplication and division (decimals)

Related environmental issues: Air / Climate change / Energy

Area level: National, State, Regional, Household

Burning gasoline in motor vehicles is one of the biggest causes of air pollution in the United States. How much gasoline your car uses is strongly connected to how dirty the air in your area is. The table below shows how many miles three cars can run on one gallon of gasoline. Those three cars are the top-8 best-selling vehicles during the first half of 2018 in the United States.

Screen Shot 2018-08-31 at 9.32.52 AM

1. Which car can go half as far as Honda Civic on one gallon of gasoline?

2. An average American drives 280 miles a week. How much gasoline does an owner of each car use on average?

3. Which car among the three is more environmentally friendly? Why? Explain.

4. If the price of gasoline today is $3 a gallon, how much money does an owner of each car need to spend for gasoline in a week on average?

5. Which car among the three would you like to by? Why? Explain.

Source: 1) Business Insider, 2018 2) fuel, 2018 3) U.S. Department of Transportation Federal Highway Administration, 2018

Note: Average Annual Miles per Driver: 13,476 miles (U.S. Department of Transportation, 2018)

Answer Key

  1. Ford F150
  2. Ford F150: 280 ÷ 16 = 17.5 (gallons)   Toyota Rav 4: 280 ÷ 25 = 11.2 (gallons)   Honda Civic:  280 ÷ 32 = 8.75 (gallons)
  3. Honda Civic: It uses less gasoline and emits less air pollutants into the air.
  4. Ford F150: 17.5 x 3 = $52.5  Toyota Rav 4: 11.2 x 3 = $33.6  Honda Civic:  8.75 x 3 = $26.25
  5. Answers may vary