We started out the assessment creating a double bubble map about electric fields and magnets, it was a fine activity. The only real issue is the focus between the articles is not that similar so in comparing the differences some students focused more on the fact that a magnet is a thing and an electric field is a field, rather than topics like electric charges having a single polarity while magnets have two. I would like to find different articles for next year, or possibly just write something of my own for them to use.
Then we moved onto the electromagnet lab. I will admit to being a bit worried about this one, I've had my students explore electromagnets before, but I've never set it up so that I had to be ready with materials for 7 periods of students to make them. As a general background, I had my students work in table groups of around 4, while this could certainly be done with groups of 2 I felt like the larger groups helped the groups be successful as more students were involved to problem solve and think of idea to test.
For the materials for the students I got:
D Batteries (I was worried about how well these would last, but each of the batteries held out for the whole day so I have plenty left for next year)
Electrical Tape (Helps hold down the wires to the end of the batteries and stop the students from getting shocked)
Nails (I got a 5lb box of 10d 3" Galvanized Nails. I don't think the nails you get really matter, but you do want steel nails. This is enough nails to last forever, because there is no reason to not just keep using them)
Sandpaper (The students need to sand off the insulation from the wire)
Paper Clips (To test the strength, though really anything with steel, even other nails, would work)
Wire (This is what I got from Amazon I gave each group about 4' and they were able to use it for all their different tests. I bought 2 rolls, but one was well more than enough. If you look closely the dimensions of the spool are not right on Amazon, this thing 3 inches high)
The groups were generally very successful in getting their magnets to work.
For the groups that were not successful at first, their main problems were not sanding off the wire well enough, not attaching the wire to actual connection points of the battery, or just not having it taped down well enough. For some groups I helped them reattach the wire to the battery, for others just slightly pinching the tape to hold the electromagnet to the battery made it work. And with that I will have a caution. These get hot, we're not talking burn off your hand hot, but a bit unpleasant. It is actually mostly the battery itself that gets hot (and any uninsulated parts of the wire). As part of my instructions to my students I cautioned them to not touch the uninsulated parts of the wire and to only leave the electromagnet hooked up when they were actually testing to give it a chance to cool.
The day after the testing was done I showed my students a video of three different electromagnets. I will note that there is always variation in how well the electromagnets perform based on just how good the connection is. (Enjoy the jolly music, it is my attempt to seem hip.)
This let us discuss what they should have observed, even if their electromagnets were not as successful or just not as consistent in how they performed.
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