Distilled water has a very low electrical conductivity, while tap water contains various dissolved minerals and ions that make it a good conductor of electricity. You can use a simple multimeter to test the electrical conductivity of the water.

1. Materials Needed:

- Multimeter with a conductivity setting

- Two clean glasses or beakers

- Distilled water

- Tap water

2. Procedure:

- Fill one glass with distilled water and the other with tap water.

- Set the multimeter to the conductivity setting.

- Dip the probes or electrodes of the multimeter into the distilled water and note the reading.

- Rinse the probes and dip them into the tap water, noting the reading again.

Results:

- Distilled water: Should have a low conductivity reading, typically below 10 microsiemens per centimeter (µS/cm).

- Tap water: Should have a higher conductivity reading, usually above 100 µS/cm.

Interpretation:

If the conductivity reading for the unknown liquid is close to that of distilled water, it is likely pure or distilled water. A higher reading indicates the presence of dissolved substances, suggesting it is tap water.

Caution: Make sure the probes are clean and dry between measurements to avoid cross-contamination and ensure accurate readings.