1. Using scissors, cut approximately a 5 cm (2 inch) piece from the drinking straw.
2. With the scissors, cut two pieces of copper wire, each about 24 cm (12 inches) long.
3. Make a conductance sensor like the one shown in the picture:
a. Wrap one piece of wire around the straw piece near one end a few times, leaving a long tail of wire
b. Wrap the second piece of wire around the other end of the straw tube a few times, leaving a long tail of wire.
Caution: Do not let the two wires touch. If they touch they will blow a fuse in the multimeter and the experiment will not work.
4. Start making the conductance measuring circuit by connecting the battery clip to the 9V battery.
5. Plug the multimeter test leads into the multimeter (Make sure to plug them into the right jacks).
6. Use a pair of alligator clips (preferably red) to connect the positive (red) wire of the 9V battery clip to the positive (red) multimeter probe. Clip an alligator clip onto the positive wire (red) of the 9V battery clip and clip the other end of the pair of alligator clips to the metal part of the positive multimeter probe (red).
7. Use a pair of alligator clips (preferably black) and attach one of the copper wire tails of the conductance sensor to the negative (black) probe of the multimeter. To do this clip an alligator clip onto the negative probe and clip the other end onto the copper wire tail of the conductance sensor.
8. Twist the other wire tail of the conductance sensor around the metal end of the black wire from the 9V battery clip.
9. Turn the multimeter to read direct current (DCA). Set the meter to 200 milliamps (200m).
10. Pour the desired liquid into a small bowl.
11. Place the conductance sensor in the bowl. Make sure it is completely submerged in the liquid.
12. Read the current on the multimeter and record it in a notebook. Taking multiple readings of the same liquid is advised in order to get accurate results.
NOTE: Make your readings quickly because copper wires will start to dissolve in the solutions. Take the initial reading.
13. Rinse the bowl and conductance sensor in water.
14. Dry the bowl and conductance sensor. Make sure there is no trace of the previous liquid.
15. Calculate the conductance (siemens) for each liquid by dividing the milliamps readings by a 1000 to convert them into amps. Then divide the amps by 9 (voltage of battery) and the liquid’s conductance in siemens is obtained.
16. Repeat steps 10 – 15 for all the liquids.
2. With the scissors, cut two pieces of copper wire, each about 24 cm (12 inches) long.
3. Make a conductance sensor like the one shown in the picture:
a. Wrap one piece of wire around the straw piece near one end a few times, leaving a long tail of wire
b. Wrap the second piece of wire around the other end of the straw tube a few times, leaving a long tail of wire.
Caution: Do not let the two wires touch. If they touch they will blow a fuse in the multimeter and the experiment will not work.
4. Start making the conductance measuring circuit by connecting the battery clip to the 9V battery.
5. Plug the multimeter test leads into the multimeter (Make sure to plug them into the right jacks).
6. Use a pair of alligator clips (preferably red) to connect the positive (red) wire of the 9V battery clip to the positive (red) multimeter probe. Clip an alligator clip onto the positive wire (red) of the 9V battery clip and clip the other end of the pair of alligator clips to the metal part of the positive multimeter probe (red).
7. Use a pair of alligator clips (preferably black) and attach one of the copper wire tails of the conductance sensor to the negative (black) probe of the multimeter. To do this clip an alligator clip onto the negative probe and clip the other end onto the copper wire tail of the conductance sensor.
8. Twist the other wire tail of the conductance sensor around the metal end of the black wire from the 9V battery clip.
9. Turn the multimeter to read direct current (DCA). Set the meter to 200 milliamps (200m).
10. Pour the desired liquid into a small bowl.
11. Place the conductance sensor in the bowl. Make sure it is completely submerged in the liquid.
12. Read the current on the multimeter and record it in a notebook. Taking multiple readings of the same liquid is advised in order to get accurate results.
NOTE: Make your readings quickly because copper wires will start to dissolve in the solutions. Take the initial reading.
13. Rinse the bowl and conductance sensor in water.
14. Dry the bowl and conductance sensor. Make sure there is no trace of the previous liquid.
15. Calculate the conductance (siemens) for each liquid by dividing the milliamps readings by a 1000 to convert them into amps. Then divide the amps by 9 (voltage of battery) and the liquid’s conductance in siemens is obtained.
16. Repeat steps 10 – 15 for all the liquids.
