[eamac]

how can you figure out which substance conducts electricity (in water)  besides testing.

[ i actually already did the testing for sodium chloride, sodium bicarbonate, calcium carbonate, potassium bromide, calcium chloride, copper (II) sulfate and sucrose but for some reason none of them made my light bulb on a circuit light]

now i cant figure out what they would have in common that would cause them to conduct electricity or which of the above would and why.

edit: i dont think calcium carbonate would because it didnt even dissolve.

edit#2: kk just figured out that NaCl ions would conduct sooo conclusion sodium chloride is likely to conduct electricity? 

[mike]

Any charged particles in water will increase its conductivity to some extent. You could therefore say that any ionic compound that will dissolve in your water should increase the conductivity.

[eamac]

well i thought because they were in water they would all conduct but they dont.

[kevins]

Have you check the circuit work or not?
Try to polish the electrodes with sand paper to remove any surface oxide of metal.
Dissolve sufficient amount of salt in water.

Try again.

[eamac]

The circuit did work cause the light bulb would light when id connect the 2 nails together, just when i put them in water it didnt work. And as for dissolving a sufficient amount we were only supposed to put tip of a splint .. im sure thats what i did