Main Introduction Initial Observation and Hypothesis Materials and Equipment Experiment Discussion Applications Conclusions

APPLICATION

Calibration Chart

The experimental results for 3 V in logarithmic scale are shown below.

The black line is the average of all three experimental series. Since the dependence of Current vs. Salt Concentration is linear in logarithmic scale it could be used as a Calibration Chart.

“SALTY ZAP”

Using our experiment results we made a simple electrical device to determine the concentration of salt in salt/water solutions.

We called our device SALTY ZAP.

SALTY ZAP is made in two modifications.

SALTY ZAP – S is a simplified modification. It only roughly indicates an existence of the salt in the water. If the concentration of salt is greater than 4% the bulb lights, otherwise it does not.

SALTY ZAP – M is a modification with a Multimeter. You have to read the data from the Multimeter and find the corresponding concentration of salt from the Calibration Chart.

The original part of the device is an Electrode Holder. It consists of the electrodes (two metal plates made from a binder clip), a plastic holder (made from a razor), a bulb (the type we used in our experiments) and plastic screws (from a toy car).

This is an electrical circuit designed on the plastic holder:

User Guide

1. Connect the Electrode Holder to the battery (S modification) or to the battery – Multimeter series (M modification).

2. Switch the Multimeter to a suitable position to measure the current.

3. Take a 40 ml sample of the salt/water solution.

4. Put the electrodes into the solution.

5. For Salty Zap-S modification the bulb lights if the concentration of salt is higher than 4%.

For Salty Zap-M read the value of the current on the Multimeter.

6. Find the value of salt concentration for the value of the current on the Calibration Chart.

NOTE: If you decide to make your own SALTY ZAP device, make a Calibration Chart for it.