For my science fair, I want to test conductors of electricity? how would i test it?

you can use water in your experiment but you have to remember one important thing, its not the water that conducts electricity but what is in it. Pure distilled water is not a good conductor. The trick would be to use well water that has a lot of iron in it. you can make your own "dirty" water conductor by dissolving anything that is conductive. You can even use plants at a low voltage/amperage. seaweed works great. And to finish your experiment you will easily find the project on line just by googling it.