Lesson 3: Watts Up?
40 minutes plus homework time
Worksheet 3, pens/pencils
Language Arts, Science, Math, Social Studies
1. Ask students to name some of the energy-saving tips from Lesson 1. As students call out the tips, write them on the board.
2. Once they are finished calling out tips, tell students that these tips were not necessary for people 100 years ago, because they were living without the technology of today.
3. Explain to students that electricity is a fairly new discovery. Tell students that less than 100 years ago, most people in the United States didn't have electricity! Ask students to think about how different things were back then. (For more information about the history of electricity in the United States, visit tvakids.com/electricity/history.htm.)
4. Have students name some household activities or chores. Ask them to imagine how those chores were done before electricity and modern technology. As students share their thoughts, draw a comparison chart on the board. Your chart may look like this:
5. Ask students if anything on the chart from the past reminds them of an energy tip of today. Guide students to understand that in the past daily tasks were more difficult and took more time, but they didn't use electricity. Today, daily tasks are quick and easy, yet we use a lot of energy to have that convenience.
6. Distribute Worksheet 3. Read the introduction text out loud. Tell students that now that they have considered the advantages and disadvantages of life before electricity, they will look at how much energy some modern appliances use.
7. Divide students into pairs or groups of three. If your students are older and can handle the problems on their own, have them work independently.
8. Give students time to finish the worksheet. Encourage students to ask questions about the worksheet if they are having trouble.
9. Assign students one (or more) of the bonus questions below. Choose the level that best fits your students.
10. Review all answers as a class once everyone has finished the bonus task. [Worksheet answers: 1) Most: dishwasher, least: DVD player; 2) Hair dryers; 3) 925 - 22.5 = 902.5 watts; 4) 22.5 x 2 = 45 watts; 5) 725 x 24 = 17,400 / 925 = 18.81 hours]
In order to enhance your students' math skills, these bonus questions have been created to challenge students of all levels. Choose the ones that are most appropriate for your class.
- Introductory Level
o If you use your microwave, refrigerator, and dishwasher for an hour each, how many watts of electricity would you be using? [Answer: 3,450 watts]
- Intermediate Level
o Most people only use hair dryers for a short time. If you were to use a hair dryer for 15 minutes a day, how much electricity would you use? How much would you use in a month? A year? [Answers: 384.4 watts per day; 11,532 watts per month; 140,306 watts per year]
- Advanced Level
o Visit http://www.energysavers.gov/your_home/ to discover the average wattage of other household appliances. Choose five different appliances and draw a chart that shows how much electricity they each use. Make sure to label your chart on each axis! [Answers will vary]