Pour the distilled water into the petri plate. Connect the graphite leads to the alligator clips. Make the circuit using LED, battery and graphite electrodes. Place both the graphite electrode into the petri plate containing water so that the current can flow and see if the LED turns on. Now add salt in the water and see if the conductivity of water increases. Now add pH solution in the water and conduct the electricity through that solution. Observe the color change as the current flows through it.