Energy is often expended when it need not be. Students will investigate the importance of turning off lights, toys, machines, and appliances.
In this lesson, students will probe the problem of what happens to a battery-operated flashlight when it is not turned off. Students will extend this context to household items like lights, radios, televisions, and computers.
This lesson is designed to begin to enable students to construct understanding of the consumption of energy by themselves as consumers. At this age, the concept of energy can be very misleading to students. Young children think of energy as being used up. They do not readily understand conservation of energy. Also, they do not understand that once energy is converted it is not necessarily in a usable form. These are misconceptions that students develop early and hold through much of their school careers.
Young children only tend to associate the word energy with moving around a lot. Therefore, it is important to help them understand the greater scope that energy encompasses. Students need to have a wide array of examples of forms of energy. It is important that they see energy-transforming devices like battery-operated toys, vacuum cleaners, cars, televisions, and flashlights. They should also begin to explore the inputs and outputs of these types of items.
Materials needed for the Extension activities include copies of the Energy-Saving Labels activity sheet from Poor Richard's Energy Almanac, carbon paper, potatoes, ink, self-adhesive notepapers, and plastic knives (or foam blocks, letters, and glue for the alternative activity).
Set out the battery-operated toy. Turn it on.
- What makes it go?
- How do we know that?
- What would happen if I were to remove the batteries?
- What do the batteries give the toy?
- What would happen if we just let the toy keep running?
Say to students, "The batteries in the toy give it energy."
Turn off the toy and show students the toy is switched off. Ask the students, "Is it using energy now? How do you know? What is energy being used to do?"
Say to students, "Today we are going to think about energy. We need to think about what it is, where it is, and how we use it. You just saw an example of a toy that uses batteries to produce energy."
- Where do batteries come from?
- Do your parents ever have to ask you to turn off your toys?
- Why do they have to ask you to turn off your toys?
- Do your parents ever get upset when you leave your toys on? Why?
- What would happen if a flashlight were left on all night?
- Do you think that the batteries would last longer if you only used the flashlight for a few minutes and turned it off?
- What would happen if a flashlight were left on just while you used it and then turned off?
Run a test as a class. Take two of the same type of flashlights. Label one as ON. Label the other as Five Minutes. Turn on both flashlights. After five minutes, turn the five-minute flashlight off. Leave the other flashlight running. Do this three times each day: morning, afternoon, and end of school day. Have the class make detailed descriptions of each flashlight. Record how long it takes before the flashlight left on no longer produces light.
- Which batteries needed to be replaced first? Why?
- Why is it important to turn off the flashlights to have longer use of the batteries?
- Which would cost more, leaving a flashlight on or turning it off?
Now as a class, discuss other types of energy in and around the house. Say to students, "We talked about what happens if a flashlight is left on. Now we need to think about other things we know of that use energy. Where would we find other things that use energy? Are batteries the only way we can get energy? What are some types of energy?"
As a class, have students brainstorm a list of as many items as they are able to think of that use energy. Write the list so that they are able to think of new examples. After they have had 5-10 minutes to come up with a list, help students think about how each item gets the energy. Remind them of the examples of batteries, outlets, and fuel as some helpful hints to get their thoughts directed.
- What happens when the television or computer is left on?
- What kind of energy does it use?
- What does energy cause the computer to do?
- Who has to pay for that energy?
- What happens if you leave a lamp on?
- What does energy cause the lamps to do?
- Who has to pay for the energy to keep the light on?
- What happens when a car runs out of gas? Where do you get more gasoline? Who has to pay for the gasoline?
- What would be a good way to try to keep from having to buy a lot of new batteries, gasoline, or electricity?
- Are there some things that can't be turned off to save energy? What are they? Why can't they be turned off?
Distribute copies of the Just Turn it Off student sheet, which depicts a room with many appliances. In order to familiarize students with the different objects in the picture, have students name and point to each one.
Say to students, "Sometimes we all forget and leave things running that we should turn off. If we turn them off, we use less batteries, gasoline, or electricity. Look at the picture in front of you. I want you to color all of the things in the picture that use energy. You do not need to color the whole picture; only the things that use energy. When you have finished coloring, circle the things that you would turn off to save money. Be ready to explain you answers."
Have students share their different items and reasons for choosing them. Allow students to voice differing opinions. (The fish tank, for instance, could lead to an interesting discussion, as some students will have familiarity with aquariums that have a plug-in filter while others will not.)
Remember that it is not as important for students to find all the things that use energy as it is for them to have valid explanations and defenses of their choices. Make sure students understand that while machines may be turned off to save energy, sometimes they can't for practical purposes.
Discuss with students some energy-efficient appliances like irons, coffee makers, and lights that either shut themselves off or can be programmed to shut themselves off. Have the students go home and with their parents try to find if they have any of these types of devices in their home. Allow a student discussion. Have students propose some new items that could easily be made to be energy efficient. Remember, it is not as important that it be an idea that would be easy to do, but it does need to be an idea that could have an impact on energy use, safety, or convenience.
Separate the students into groups of four or five. Pass out the Energy-Saving Labels activity sheet, from Poor Richard's Almanac, part of the Energy Quest website. Say to students, "Sometimes, we all forget and leave things running that we should turn off. If we turn them off, we use less batteries, gasoline, or electricity. It is a good idea to give ourselves reminders so that we get used to turning off our things when we are done with them. We are going to make one type of a reminder to help get in the practice of turning off things to save money and energy."
Hand out potatoes that are cut in half to each group. Have students follow the printed instructions for the potato stamp. Make sure that you read all the instructions one at a time to help students follow them. Allow students to print several stamps to take home. Remind them that they are to use the stamps as a reminder to themselves to turn things off so that their household can save money. As an alternative to this activity, use foam blocks and soft foam letters to create the stamp. This allows younger children to safely assemble the stamps with little or no cutting.