yr metals conductivity

[Ocean Breeze]

We are up to the yr 8 topic Heat

I am wondering if we could all share our method of attaching the drawing pin/match-head to the metal rods( Cu, Al, Fe,etc).

(An object is attached to the rod using paraffin wax, plasticine etc. The ends of the rods are heated at the same time, and the last object to drop off the furthest end of the rod, is the least conductive metal)

I have some greater or lesser success over the years with the various methods.
Share?

[RosalieM]

Sorry rainbow-sky,
I don't think we do that prac here.
Rosalie

[Sassi]

I think we just used a bit of petroleum jelly to attach the beads, we use different coloured beads instead. It worked really well, actually

Cheers, Sassi

[Whspa]

We use petroleum jelly as well.

Carol

[cactus155]

Wax is what is used when I have done that exp. before, haven't done it for a couple of years now though.

[rae]

Hi,

We use dryed peas attached with candle wax or parrafin wax and there has been no complaints. We have the conductvity cross thingy with the ring. Is that waht you use??

Lorrae

[dime]

We have also used parrafin wax and drawing pins. But the teacher just asked me to buy conductivity rings, which she said are easier (used at a previous school).

[lada]

We , too, use the conductivity cross thingy. I have wax pellets, place one in each corner of the cross and put a pin or a very small object into the pellet. the pin that falls first is on the most conductive metal arm.
Lada

[Ocean Breeze]

Thanks guys
Me, I usually use the rods with a coloured pin attached by a blob of paraffin wax, at regular intervals.

We also have the conductivity "cross thingy" with 4 metals at right angles. Problem with this one is that the wooden circle support may get burned, so is usually done as a dem, with limiting gas to a small flame, but on a hot flame. Using paper clips embedded in wax, with a coloured "flag".

The other conductivity "thingo", is a single unit of 6 radiating rods, one of which is the handle. Fill each of the holes with a cut-off match head, right side up, leaving a little of the wood . Be careful with this one though, demo only, as it can "spit". Always wear protective gear, and cover the bunsen hose with a damp cloth or something. Good effect though.

Oh, and of course the bimetal strip is always a winner

Keep the ideas/methods coming in.....

[Jen1]

It is possible to buy the conductivity "cross thingy", which I call "wax wheels" with a metal circle support because as you said, rainbow sky, the wood ones do tend to get burnt. I have thrown out all the old wooden ones and replaced with metal ones, bought from Haines or Science Supply i think. I put a drop of wax in each and add a marble which makes great excitment for the kids when they fall and go bouncing off to the floor. Perhaps paper clips would be better for the teachers sake but I dont want to be the spoil sport!

We also use the bimetalic strips and bar and gauge (bar heats up, expands and doesnt fit the gauge anymore) and ball and chains with circle that ball will fit through when cold and wont when hot.I have just bought conductivity rods but they are very thin and I've broken one already!!

[kitty kat]

HI, we use a special divice that you can by from Q-stores or serrata .you heat the middle with a candle and place the wax in the indent at the endof the differerent metals it is great.

[Lyn]

We have used small beads attached with margarine to the metal rods. Like most things it is a little messy but fairly easy to clean up afterwards. Apply margarine with a spatula or paddle pop stick depending on how much washing up you want to do.
Lyn.

[Tina]

Hi
We use bars of 2 different metals and glass, clamped to a retort stand. The ends of all three sit above a bunsen. I light a candle and drip candle wax at regular spacing along the rods, then stand a match in each drip. Then we light the bunsen and time how long it takes the matches on the different rods to fall down as their wax drip melts. This can be used as a graphing exercise or just a demo.
However, I love all the ideas put forward here. I am going to investigate this conductivity cross thingy and I am definately going to experiment with marbles. The matches can be difficult to see from the other side of the room. Marbles are more colourful ... and noisy when they drop! What more could you want.

[Loopy]

Hi everyone,
I bought several types of conductivity rings from a couple of different places in the past three years and can highly recommend the ones sold by Science Supply Australia. Although they are $28 each they have a good metal ring in which each metal is riveted to. Having bought some cheaper ones that aren't worth a pinch of snuff, these ones are made to go the distance.
Lou.