Does water conduct electricity?
This Topic is About...
- I will investigate if water conducts electricity.
- I will identify and explain risks and carry out practical work safely.
- I will make predictions and check if results support or do not support my predictions.
- I will make a conclusion from the results.
- I will identify risks again and make sure practical work is done safely.
You’re going to be a science explorer!
Key Words
- distilled water
- pure water
Tap to Learn the Meanings!
- distilled water: Water that has been boiled and cooled to remove all impurities and minerals.
- pure water: Water that contains only water molecules, with no dissolved substances or contaminants.
Nice work! You’re learning about clean and purified water types.
Is water pure?
Water from a river or the tap is not pure water. It has salts dissolved in it. Distilled water is pure water. Distilled water is water that has been boiled and the steam has been allowed to cool down to form liquid water again. This water is distilled water and contains no salts.
All living things contain water. Our bodies are about 65% water! This water has salts dissolved in it so it is not pure.
Let’s Investigate!
Question: Does water conduct electricity?
Equipment: A circuit with two 1.5 V cells in a cell holder, a piece of plastic-coated wire, distilled water, a beaker, two teaspoons of salt, aluminium foil
Method:
- Connect the circuit with the cells, the lamp in the lamp holder, and one length of wire.
- Test the circuit by holding the crocodile clips together. Does the lamp light up?
- Fold two pieces of aluminium foil and put them into the crocodile clips at the end of each wire. This gives a larger surface area in contact with the water.
- Pour 250 ml of distilled water into the beaker and dip the aluminium foil ends into the water.
- Predict whether the lamp will light up.
- Observe whether the lamp lights up.
- Remove the aluminium foil ends from the water.
- Add two teaspoons of salt to the water and stir well.
- Dip the aluminium foil ends into the salt water. Predict whether the lamp will light up.
- Observe whether the lamp lights up again.
Follow-up Questions:
- Did your results support your predictions?
- Compare the results you got with pure water and with salty water.
- What conclusion can you make about whether water conducts electricity?
- Would your body be a good or a bad conductor of electricity? Explain why.
- Use your answer to question 4 to explain why it is not safe to touch bare wires when the circuit is closed.
- Why is it dangerous to swim in the sea when there is a thunderstorm with lightning?
Tap to See Answers
- 1: The results likely matched the prediction that pure water is a poor conductor and salt water is a good conductor.
- 2: The lamp did not light with distilled water but did light with salty water.
- 3: Pure water does not conduct electricity well, but salt water conducts because the dissolved salt forms ions that carry charge.
- 4: The human body is a good conductor because it contains water and dissolved salts that allow electricity to flow.
- 5: Touching bare wires is dangerous because electricity can pass through your body to the ground, causing injury or shock.
- 6: Sea water is a conductor; during a thunderstorm, lightning can travel through the water, making it dangerous to swim.
Excellent reasoning! You’ve shown how ions in water affect its ability to conduct electricity — and why electrical safety is so important.