I’m getting ready to start work with fourth graders on electricity and magnetism. We’re in remote learning, so I need to send kits home for the kids. I have a budget of about $5 per kid, although I can maybe stretch this up to $6. I’d love for kids to learn the following things:
-How to create a circuit
-How electromagnetism works
-A little bit about how magnets work (although Insane Clown Posse is right, last time I went down that rabbit hole I ended up trying to understand some quantum shit, it’s pretty complicated).
For each kit, I think I need:
A D-cell battery
A 1.5 V light bulb
A 2’ length of wire and a 1’ length of wire (2’ for the magnet; the 1’ could be shorter, but I want enough wire that they can create the circuit easily)
A 1’ square of aluminum foil
A 2" iron or steel nail
3 small metal paper clips
a Ziploc quart bag to hold it all
With these items, kids can create a circuit to light the bulb, and they can wind the wire around the nail to create a weak electromagnet, and they can test whether aluminum conducts electricity.
What I’m not sure about:
-What gauge wire do I need to buy?
-Are there items you’d suggest I add or subtract? Remember my budget, and also consider I’ll need to put ~80 of these kits together, so I can’t make them crazy-complicated.
FWIW, the standards I’d address in an ideal world include:
Iron filings. You need something to show that a weak electromagnet is working. With filings you can show a wire just bent around in a loop to touch both ends of a battery will create a magnet. You can also illustrate magnetic field lines around stronger magnets using the filings.
Also, a small plastic bag or bottle to hold the filings, and a piece of tape to cover at least one end of the battery so it doesn’t short out inside the bag. I suggest using magnet wire for the electromagnet experiments, and include a little piece of fine sand paper to clean off the insulation.
Thanks! What’s magnet wire? I’m now finding experiments that say 22 gauge wire works. I was thinking about tape, but I’m really not sure how to send home strips of tape; maybe I put the battery in a separate bag or envelope within the bag. Iron filings are interesting–the experiments I’m finding say that paperclips can show their effects, but you’re right that the filings could show fields. I may do this as a demonstration, though, instead of trusting 80 kids at home to manage their filings
Very thin wire and thin insulations works better. But you do need to sand off the ceramic insulation, no biggie, that by itself fascinates some kids. If it’s a budget issue let me know.
I’m not sure this is accurate, unless there are values of “quickly” that I’m not thinking about. I’ve done this experiment before, albeit 15 years ago, and none of the kids had red-hot wire.
Tripolar, that magnet wire looks interesting, but I’m worried that it’ll require a greater length of wire than I want to put my kids through. 22 gauge wire might work better just because you can get a noticeable magnetic effect with 15-20 wraps. Am I wrong on that?
A foot of #42 magnet wire will give you ~1.5 Ohms resistance for an amp of current, That could work if coiled, but it’s going to dissipate over 1.5 Watts of power. So, yes, it only requires a touch to cause the filings to react.
You can get 22 gauge magnet wire also. @Crane knows this stuff well, I just did these experiments when I was a kid. Batteries were a new thing back then, many people still called them phlogiston reactors and magnets were known as Devil’s Teeth.
Cool. I’m pretty ignorant about basic electricity vocabulary, so I need to read up on it. Thanks!
As for magnet wire, I’m still a little confused: if I don’t use magnet wire, will it still work? Sanding off insulation would be really tricky for me to direct from a distance. Plenty of kids taking the lesson won’t have an available adult to help them if they’re confused, so I want to make the lessons as foolproof and straightforward as I can. If I can get away with using wire that doesn’t require sanding, all the better. (Although I just realized I’ll need to strip insulation away from like 1/2" of each end of each wire length, right? yikes. Fortunately I think there’s a bus driver at my school who needs the hours, and hopefully she’ll be able to help with assembling kits).
I don’t think it’s necessary. The insulation on 22 gauge will be pretty thin anyway and shouldn’t make a lot of difference in getting iron filings to move. How many kits do you need? Stripping wire isn’t going to take up that much time.
Magnet wire is pricey these days. The thin insulated stuff they use for phone circuits will work fine. You will have to strip the insulation off of the wire ends. You don’t want kids carving it with a razor blade. Leave the insulation on the rest of the wire and wrap it around a nail. Then only touch it to the battery.
You can get away with a quality AA battery rather than a D for these experiments. A small square of fine sandpaper (400) is great for the kids to strip the ends of the magnet wire themselves, just be sure the magnet wire is brightly colored, not using clear lacquer. A 12D galvanized nail (3.5") is a good size for an electromagnet, it’s chunky and easy to hold, and takes about 4 feet of wire. Paper CD cases are useful to package small lengths of magnet wire.
I’m doing ~80 kits, andCheesesteak, your comment about sandpaper clarifies something that TriPolar was saying and I wasn’t getting: the sandpaper would be in lieu of my stripping insulation from the ends, right? That doesn’t sound too bad, and could be something I could do with the kids even remotely.
Beowulff, that motor looks awesome, but something to do when I can be in the room with them again.
Okay, here’s what I plan to order.
Batteries are weird: I had to get 3 different batches, because they wouldn’t let me get more than 2 of any batch for some reason.
125 sq ft foil (might use this to create a circuit board, otherwise to test conductivity of other metal)
500 3-inch nails (more than we need, but I couldn’t find an amount between 66 and 500)
240 1-cm refrigerator magnets (these are tiny, and we’ll need to include a “keep out of reach of toddlers” message–but that’s true for a lot of this stuff)
2 50-packs 1.5 v light bulbs (these are like flashlight bulbs. I didn’t get LEDs only because I’m not 100% sure the wire connections will work easily)
LHD - something you might try is wrapping a tight coil (strands next to each other) of any light weight (22) wire around something like a water bottle or broom handle. If you remove the coil and sit the coil on a surface and touch the wire ends to a D cell, the individual turns should spring apart. That might be a simpler demonstration.
Getting the insulation off of magnet wire is not trivial. It’s tough stuff.
Crap. I think I won’t do iron filings this time–again, due to needing kids to be able to do the experiments without an adult in the room. Iron filings are probably too messy. (Also, my school secretary was like, put the order in now, so I just did, and forgot the iron filings). I might send them home with another materials distribution in February.
