electrical circuits question - safety- primary teachers help!

[picnicinthewoods]

I'm running a session tomorrow with primary age children & one of the activities involves making a simple circuit. I have enough crocodile clips for everyone to make a circuit but then thought it would be great if they could add a switch to their circuit. The problem is I don't have any more crocodile clips just electrical wire. I've stripped the ends of some electrical wire to expose the actual wire & just wanted to know if this would be considered safe for kids aged 5-8 years to use? They are only lighting a bulb with one AA battery, but obviously they could connect it up and put the battery in the holder last and leave the switch off whilst they are doing this. Safe or not safe? primary teachers out there, would you do this??

They are not going to electrocute themselves with a AA! But the wires may get hot. If they just hold the covered bit and touch to make a connection for a short time that should be ok. Or work in groups and take turns? How many sets have you got?

No that's what I thought!!! I have 15 kids and 2 crocodile clips each so they can make their light bulbs work (they are making lighthouses) & then I have enough wire for all of them to add a switch. It's just if they add a switch they will need the wires to connect so will need to twist them around each other, do you see what I mean?

They are supposed to be taking the lighthouses home with the circuits intact.

Actually they will take it home next week as its a two week project. Maybe I should get more clips and just demonstrate the switch part tomorrow?

In one school I taught year 6 in there weren't any crocodile clips, just electrical wire which then had to cut to length and then strip with wire strippers. I still have nightmares about teaching circuits there.... We used to use electrical tape to hold the wire over the battery terminals. (It wasn't a nightmare because of safety reasons - more the logistics of 32 children and 2 sets of wire strippers, and circuits failing all over the room because they hadn't made a decent connection at the terminal, with me racing round the room like a whirling dervish fault finding).

Will they be making the switch themselves? I think year 4 normally do that (paper clip and 2 split pins on a piece of card) so if the ones you have are 5-8 that might be new to them. But they should all have made basic circuits in year 2 so they should have done it before.

In answer to your question, I don't see any problem with them using wires rather than crocodile clips. If you have tape to hold the connections with, so much the better.

I used batteries for electric circuits with Y5/6 pupils last month. We had packs with 4 x D batteries. They had a play with our wires but nothing bad happened. They had fun experimenting with bulb brightness.

I didn't even consider it to be a risk (on guidance from Physics dept - I'm a Biology teacher but was doing a Science day at my DSs' school) :)

Ok fab, that's makes my life easier if I don't have to go and get more croc clips. Do I need electrical tape to hold it together or would selotape (!!!!) suffice???!

Have you tested your circuit? Your bulbs might be different, but I did struggle to light a bulb with an AA battery, although I was passing the current through water (to demo that salty water conducts electricity!)

So you have bulbs, holders (proper ones with places to plug in wires?), a battery (in a holder with terminals?) and are going to make a switch or touch wires to switch terminals?

Does it have to be done tomorrow? A friendly secondary school should lend you all the equipment. Mine would :) Where are you?

If they construct it so that the last bit of the circuit they connect is one of the crocodile clip connections, that might make it easier - so nothing can be live while they're fixing the non-croc connections in place.

Yes that makes sense Errol.
They don't have to have a switch, I just decided at the last minute that it would make it better.
I have x2 croc clips each, a bulb and holder & battery and holder each. I've tested the circuit and it works. I was going to get them to make a switch (card, fasteners and paper clip) & then attach this using the wire.

Could attaching and detaching the croc clip be the switch? Or if you want to demo you could directly attach the wire to the holder and secure with tape and use the 2 croc clips as a switch you clipped together.

Yes, that would work fine. Sounds like they'll have fun :) great idea re croc clips last - good practise if nothing else. 1.5V will be negated by resistance of the skin - otherwise you'd get a shock holding a battery with a finger at each end :)

The thing that would concern me slightly would be that they might take away the idea that it's not that dangerous to touch a bare electrical wire that might be live. OK it isn't that dangerous if you're only connecting it to a small battery but it would be if it was connected to the mains.

Making the final step the crocodile clip one would help a bit with that, perhaps with the last but one step being the battery going in so that they get the idea that the bit where you twist the wires together happens only before the electricity stage.

Overall though I prefer the idea that bare electrical wires are Something We Never Touch, for children that age (and I say that as someone who studied physics and who generally believes in hands-on learning).

Thanks guys, Im going to bed now to sleep on it! I prefer the idea of them learning to never touch bare electrical wires too. At the very least I will ensure the battery is the last thing to go in..........I might just demo the switch and get them to add it next week when I can organise extra croc clips. thanks for all your replies, so helpful:)