This builds on the prior lesson, Energy Transfers 1, where students identify energy transfers in everyday items and objects from the natural world. In this lesson students push their thinking further to identify multiple energy transfers that work within the system.
They begin by responding to a toy that the teacher holds up which demonstrates a few different energy transfers. Similar to the opening activity in the previous lesson where the teacher shows flashlight in this demonstration the hook is a toy. This connects to the remainder of the lesson where the teacher gives each table group of students a different type of toy that demonstrates different types of energy transfers.
Students will work together to determine as many energy transfers as they can and creates a poster of these energy transfers to share with the class.
Key concepts include:
To capture students' attention and model what they will be doing in this lesson hold up a wind up toy, wind it and let it go. After the students have a few moments to react, ask them what forms of energy were observed in the windup toy demonstration. Record their ideas on the board and then ask them to identify the types of energy transformations between the forms. For instance, mechanical to stored mechanical to mechanical (motion) and sound.
As you write these out on the board, connect each energy transformation with an arrow. If one transformation results in multiple forms of energy, such as sound and motion, separate these either with the arrows going off in different directions.
Next, tell students that their group is now going to have an opportunity to identify (observe/explore) a toy's types of energy and energy transfers. They use their science journals to record the various forms of energy and energy transformations that they identify and then working as a group, create a large energy flow diagram on poster paper. They should use a picture and a word to describe the form of energy as well as what type of energy it's transforming into.
Before students get started, let them know that they have 20 minutes to work on this and then each group presents their posters to the class.
Hand out the toys to the groups and let them get to work.
Once the students get to work, you will want to manage their excitement interacting with the toys. Depending on your group of students, the the toys can really get them wound up, pardon the pun. Accept that they will want to play with them initially, but then it’s time to get down to work. After a bit of play time, prompt students to stay focused and then listen to their discussions about the types of energy transfers that they are noticing. If some groups are missing energy transfers you might prompt them with some key questions as you listen to their table conversations.
Be aware of the time, and make sure that the students have had ample opportunity to create their posters. When the class is ready, call individual groups up to share both what their toy was and how it behaved along with the types of energy transformations they identified. I like to help critique each poster by having a stack of sticky notes and marker handy. After the group presents, I turn to the class and ask them what they think. If there are energy transfers that the group got wrong, or missed, I write the correct answer or missing transformation on a sticky note and place it on to their poster to create a completed diagram.
As your students are talking, keep in the back of your mind how they are processing the conservation of energy. I always think of it this way, if at the beginning of the system you start with 100 energy “units”, are you left with 100 at the end and if not where did they go?
You could even use this analogy with students at this point, although I save the quantitative measurement for a different lesson. Keeping the idea of generic energy units though is a safe entry point for most students and they will be able to start thinking about where the energy is going and how much is being transferred from one form to the next.
In the video below I asked one of my students reflect on how using this model helps them make connections to how energy transfers in the system.
As an extension to this lesson, you could assign Energy Transformations Practice for homework. In addition, I have also asked my students to consider any device in their home and create an energy transfer diagram for that device, labeling each transformation.