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WISHD: Can the table have energy?

September 12, 2012

Setting: Students are sliding a wooden block across the table and thinking about what happens to the energy in the block once it stops sliding (part of a PET activity).

Student: Can the table have energy even though it isn’t doing anything?

Me: I ask if the student is wondering whether the table can have energy even though we don’t see the table moving or stretching (we’ve so far introduced kinetic and elastic energy in class). The student confirms this is her question, to which I respond “hmm… I don’t know.” I follow this up with more unproductive comments that fail to help anyone.

What I Did Wrong: I played the ‘I know something you don’t know, and I’m not going to tell you’ game. This usually frustrates students (as it did here) and it fails to gain me any further insight into the student’s thinking.

What I Should Have Done: I should have started by pointing out that the student is asking a great question. The fact that she sees a conflict between 1) thinking the energy has to go somewhere, and 2) thinking that if the energy goes into an object then we should see some kind of effect in the object, shows a good deal of understanding about how scientists think about energy. From here maybe I ask the student which answer she would find more satisfying: a) that the energy disappears, b) that the energy goes into the table and has no effect on the table, or c) that the energy goes into the table and effects the table in some new way that we haven’t yet trained ourselves to notice. Then I ask the student why she finds either a), b), or c) most satisfying and tell her that’s what she should write down as her answer. I assure the student that by the end of the activity she will have the evidence she needs to answer this question with confidence.


Setting: Same activity as above but slightly further along. Students are now filling in a source/receiver energy diagram for the block and the table.

Student: Shows me the diagram in the book to which she has drawn in an additional step showing energy from the table being transferred to the environment. She asks if this is correct.

Me: I ask if the student is trying to show that the energy doesn’t stay in the table forever. She confirms this and asks if she’s correct. I tell the student to flip ahead in the book to the end of the next section and show her a diagram in the book very similar to hers.

What I Did Wrong: I presented the book as the source of authority over the student’s own experience and logical deductions.

What I Should Have Done: I should have asked the student for an example or life experience that supports her idea that the energy doesn’t stay in the table. I then applaud the student for thinking through the scenario and trying to make sense of everything rather than automatically stopping where the book stops. I ask the rest of her group if they agree with the student’s idea: if they do then I say it sounds like she’s correct, if they aren’t sure then I suggest the student keep her full diagram as a record of her thinking and then return to this question at the end of the activity to see if the group can reach an agreement at that point.


From → Teaching, WISHD

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