# Energy is NOT Always Conserved!

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## Objective

Students research the process and applications of nuclear fission and fusion.

#### Big Idea

Energy can become mass and mass become energy through the relationship of E=mc^2

## Context and Supplies

Access to the internet or classroom resources about nuclear fission and nuclear fusion is needed for this activity. Students work in groups of four to do a jigsaw activity. Two of the students research nuclear fission, what it is and where it happens and two of the students do the same for nuclear fusion.  The research portion lasts about 15 minutes. Then students teach the other students in their group about their topic; the groups then switch roles.

CCSS Math Practice 2: Reason abstractly and quantitatively is applied to this activity as is NGSS Science Practice 5: Using mathematics and computational thinking and Science Practice 1: Asking questions (for science) and defining problems (for engineering) and Science Practice 8: Obtaining, evaluating, and communicating information. This is done in the context of HS-PS1-8Develop models to illustrate the changes in the composition of the nucleus of the atom and the energy released during the processes of fission, fusion, and radioactive decay and HS-PS3-1: Create a computational model to calculate the change in the energy of one component in a system when the change in energy of the other component(s) and energy flows in and out of the system are known. In this case, the energy flow is mass into energy and energy into mass as it relates to E=mc^2.

## Class Discussion on E=mc^2 Research

5 minutes

I instruct students to get out their E=mc2 research homework which was assigned last class. I ask the question of the class, "What did you learn about E=mc squared?" While student speak about some of the things they learned from completing the assignment, I walk the room and check to see that students completed the homework. There are different ways to use homework, sometimes I assess student understanding of the topic by giving a quiz and sometimes I collect the homework and grade it for correctness. The purpose of this assignment was to expose students to Einstein's famous equation and its meaning; for this assignment, I check for completeness and assign a grade for effort. I usually grade homework out of 6 points. If students have a complete assignment, they get 6 points, half done gets a 3, etc. Students know that full effort on homework will benefit both their understanding of the material and their grades on quizzes and tests. After I enter the grades and discuss what students learned, I call on random students to provide answers to the homework sheet.

## Jigsaw - Applications of E=mc^2

40 minutes

After we review the homework sheet and students know that E=mc^2 is significant in only the most extreme of circumstances (center of the sun, atomic bomb explosion, radioactive decay, etc), we start the jigsaw activity. In this activity, students are expected to learn one particular concept in-depth and then share their knowledge with their peers. On the board is the following information which students use to complete this task.

Fission/Fusion

• What is it?
• Where does it happen?
• How is E=mc^2 involved?
• How is it applied/used?

Students draw a diagram to show the process of fission/fusion as a part of their explanation.

My classroom arrangement has students in groups of four, and that is the grouping for this activity.Two students research fission and two students research fusion. They have 15 minutes to use the available textbooks and internet to answer the questions. The room is quiet during this time.

After 15 minutes, students should have their research finished and the above questions answered. In their groups of four, they share out their answers with their peers. Everyone is expected to write down what they learn from the student teacher. One of the reasons I have two students per item to research is so that they help each other fill in gaps.

## Fission/Fusion Review

5 minutes

For the last 5 minutes of class, we review the questions from the jigsaw activity. I call on random students to answer the questions.

Fission/Fusion

• What is it?
• Where does it happen?
• How is E=mc^2 involved?
• How is it applied/used?

The goal is to clarify any misunderstandings or mistakes. For homework, students are to complete the Energy quiz preparation. I inform students that there is a quiz in two days on the material that is on this worksheet. The goal of this sheet is to help students assess their own understanding, what content they know and can apply and what content they need help with. I ask students to work independently on this sheet since they use it to self-assess their understanding. I encourage students to have their notebooks and past worksheets with them so that they can review their work while they review.