Energy Lesson Six
Safety Precautions: Students should wear safety glasses when operating a caulking gun. Rubber gloves should be worn as an extra safety precaution. Caution students not to loosen or scrape old paint in buildings built before 1978 unless the paint has been tested to ensure that it does not contain lead. Cut all of the caulk tube ends yourself. Caution students not to touch the light bulbs after they have been turned on to avoid burns.
1. Introduction.
What is the difference between energy conservation and energy efficiency? [Energy conservation is the act of using less energy, for example, by turning off lights when leaving a room or walking instead of driving. Energy efficiency has to do with the amount of energy that enters a machine or appliance that is actually used to perform its function vs. the amount that is wasted. For example, a car that gets 35 miles per gallon is more energy efficient than one that gets 25 miles per gallon. By choosing energy-efficient electrical appliances, heating and cooling systems, vehicles, and other products, we can complete the same task as with a standard product but use less energy.]
Handout copies of Energy Use of Some Typical Home Appliances student resource and discuss the energy use of some typical home appliances. Display the ENERGY STAR overhead transparency. ENERGY STAR products meet energy efficiency guidelines set by the EPA and U.S. Department of Energy. These products use less energy than comparable products, although they are sometimes more expensive to purchase.
The payback time, the amount of time it takes to recuperate the added cost of the product in energy savings, can be calculated to help you make purchasing decisions.
What are the benefits of energy conservation and energy efficiency?
By using a few inexpensive energy conservation and energy efficiency measures, we can reduce our energy bills by 10-50% and, at the same time, help reduce air pollution, protect our energy security, and ensure energy supplies for the future (U.S. Department of Energy, 2003). For example, if we reduce the amount of energy derived from fossil fuels, the amount of greenhouse gases and air toxins released into the environment also will be reduced, our energy bills will be lower, and there will be more energy resources left for future use.
2. What are some strategies you could use to conserve energy and increase energy efficiency?
Lead a class brainstorm of ways students can conserve energy and increase energy efficiency. List the student responses on the board.
Have students list five more ways they can conserve energy in their daily lives on Ways to Conserve Energy and Increase Energy Efficiency student activity page. Have students place a star next to the strategies they are willing and able to implement.
3. Display the Sources of Air Leaks in the Home overhead transparency.
Identifying and stopping air leaks is an easy and affordable way our families can save energy and money. The number one contributor to higher heating bills and its resulting pollution is air leaks.
How can we identify places where air leaks occur? Demonstrate how to identify air leaks with an air leak indicator. If the tissue paper moves, it indicates that air is leaking in or out of the building in that location. (Be aware of updrafts from heaters, which will move the paper, but which do not indicate air leaks.) Have students build air leak indicators to take home.
4. Present ways of fixing air leaks.
Describe caulk, weather stripping, insulation, and draft dodgers. [Caulk can be used to fill cracks, gaps, and joints less than ¼ inch wide. Weather stripping can be used around leaky windows and doors with gaps greater than ¼ inch wide or where caulking is not practical. Draft dodgers (stuffed cloth tubes) can be placed at the bottom of doors.]
Demonstrate how to load and operate a caulking gun. Show students how to smooth the bead of caulk using their finger and/or the back of a plastic spoon. See the How to Caulk teacher resource for more information. Have students practice running a bead of caulk on a piece of cardboard until they are proficient. (Cardboard box tops work well.)
Assign Identifying and Fixing Air Leaks home activity. (Students complete a pie chart showing where leaks occur. These can be compared to the data shown in the overhead transparency Sources of Air Leaks in the Home before tomorrow’s lesson.)
5. Students conduct the An Enlightening Investigation student activity. (The teacher answer key is attached at the end of the lesson plan).
Show students an incandescent and compact fluorescent light (CFL) bulb.
Have students record their predictions in step 1. Then have them complete the investigation and record their observations.
Notes: Steps 7 and 8 of the investigation are optional and require a darkened room. Sample data tables are not provided because data will vary depending on the wattage and brand of bulb and the temperature and light level units. Make sure students record the temperature and light level units on the tables and graphs. You may need to help them determine appropriate scales for the graphs and help them with the calculations in steps 18 and 19.
6. Review the An Enlightening Investigation data. Have students compare their results to their predictions.
Which light bulb is more energy efficient? [Compact fluorescent.] How do you know this? [The incandescent bulb gave off more heat energy than the compact fluorescent bulb, so that means that it was less efficient at converting electricity to light during the energy transformation. Incandescent bulbs only emit 10% of their energy as light and the rest is emitted as heat energy, whereas most CFLs emit 90% of their energy as light.]
Which light bulb costs less to operate? [CFL]
Which light bulb costs more initially? [CFL]
How much energy and money can you save per year by replacing one incandescent light bulb with one compact fluorescent light bulb? Assume the light is on for 10 hours each day. (Answers will vary; see the answer key for sample responses.)
How long will it take for energy savings from the compact fluorescent bulb to exceed the added initial cost of the bulb? (Answers will vary; see the answer key for sample response.)
7. What are the advantages and disadvantages of each bulb? Compare incandescent and CFL bulbs using the Incandescent vs. Compact Fluorescent Light Bulbs and the Incandescent vs. Compact Fluorescent Light Bulbs Advantages and Disadvantages overhead transparencies.
Each type of bulb has advantages and disadvantages. The amount of lumens (light brightness) emitted by a bulb is one way to compare incandescent and CFL bulbs. Compact fluorescent light bulbs are more energy efficient, last ten times longer, and use 1/4 the energy incandescent bulbs use to produce comparable light levels. However, they cost more initially, may be hard to find in rural areas, and take longer to reach maximum light intensity.
Lead a classroom discussion: Which bulb would you choose to purchase and why?
If everyone in the U.S. replaced one incandescent bulb with an ENERGY STAR qualified compact fluorescent light bulb it would save an amount of pollution equivalent to removing 1 million cars from the road [U.S. Department of Energy, 2004].
Should the government legislate that we use compact fluorescent light bulbs for the common good or provide incentives for purchase? What else might be done to encourage the use of energy efficient lighting? [Answers will vary, but might include higher tax on incandescent bulbs, energy efficiency educational programs, trade-in (an incandescent for a CFL) programs, etc.]
8. Summary Understandings.
We can use data and tools like the ENERGY STAR logo to help us make better decisions about personal actions that affect energy and resource use. By using a few inexpensive energy conservation and energy efficiency measures, we can reduce our energy bills, reduce air pollution, protect our energy security, and ensure energy supplies for the future.
9. Assign the Week 2 portions of My Environmental Diary from Lesson 1 if you haven’t already done so.