Australia's Science Forum

Dear All - Has anyone had success getting a deflection on a micro-ammeter or multimeter using a length of Nichrome wire and two lengths of copper wire (ends cleaned!) Join one end of each copper wire to each end of the Nichrome wire by twisting together and the copper wire ends to the multimeter or micro-ammeter. Put one junction into a beaker of crushed ice and the other junction into a bunsen flame and heat to red hot. Should get a deflection! Anyone had any luck? Your input would be appreciated. Thanks. Jude

Our kids do the same practical and they seem to get a reading on multimeter.
Lada

Thank you for that Lada, we are not having any success!! What thickness is the wire? The wire we are using is 22swg, maybe it is too thick? Any tips? Cheers. Judy

I would not even bother with the iced junction. Just use TWO dissimilar metal wires with ONE junction Wrap the copper and Iron (or NiCr) wire together and heat the junction in a strong bunsen flame.

I have just done it this way and got about 20 micro (u) amps without even cleaning the ends of the wires!

Cheers

Ian

And try a galvanometer instead.

Thanks everyone - I'll ditch the ice junction and try again with the multimeter/micro-ammeter see if that helps and if not try the galvanometer. You've been most helpful. Cheers. Judy

I bought some lovely little thermocouple rigs from Scientriffic that even have banana plug outlets on them, and they worked like a dream!

Success at Last!!!! Thanks guys. Jude