Which metals conduct electricity best.

[lmartin]

My son is doing a science fair project showing which metals conduct electricity best by connecting a wire from a battery to a piece of metal and then to the lightbulb and checking the brightness of the lightbulb. Where can we get or what can we use for the metal. We need varying types of metal of the same size.

[deleted-71588]

I suspect that your battery and lightbulb circuit might not show any differences between most metals unless there is surface oxidation / corrosion (rust, aluminum oxide, etc) on your metal samples. Most metals are extremely good conductors and the difference in their conductivity only show up with small cross sections in long pieces.

For example, the reistance of a foot #44 AWG copper magnet wire (extremely thin) is about 2.5 ohms. Thermocouple wire would be one source:
Type K - chromel - alumel
Type E - chromel - constantan
Type T - copper - constantan
Type C - tungsten 5% rhenium - tunsten 26% rhenium
Type M - nickel alloys of molybdeum - cobalt

Other than thermocouple wire, I have no idea where you could come up with long pieces of metal with uniform small cross sections. Unfortunately, thermocouple wire is fairly expensive.

Your son might want to rethink the materials to include things other than just metals.

Something inexpensive would be to use the same measurement setup to measure compare the conductivity of various solutions of various salts. Sodium Chloride, Baking Soda, Baking Powder, Potassium Chloride (one of the table salt subsitutes), Epsom Salts, etc. This would require using a scale that can measure small amounts. The advantage of measuring things like this is that you can always dilute with more water or add more salt or change the distance between the probes to get the samples within a range that your measurement apparatus can detect differences.

The down side is that it is wet and has the potential for spills.

[deleted-71785]

lmartin,

I think Craig is right you are really going to have to make things long to see a difference.
You could try very long pieces of flat metal such as Aluminum foil. The trick is not to bundle the long piece up, but keep it as one long circle. This would only tell you about the resistance of Aluminum. There are other conductive materials around like the cars in your garage. Be creative maybe you have an iron railing in your house? You could make you leads longer and vary the length of the test metal until you see a change in the light bulb.

Regards,

-VinceMotorola