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Do Liquids Conduct Electricity

We can use the same tester which we use to test the conductivity of materials which are in the solid state for the liquids also. Before using the tester we must check whether the tester is working properly. Connect the tester to a simple circuit with bulb and battery. Check whether the connections are proper. If the bulb glows the tester is working.



In some cases there may also be a problem with the bulb and the bulb will not glow in that case tester is used to check the current flow in the circuit.

Take lemon juice in a small trough and connect it to a bulb and a battery along with a tester. Check whether the bulb glows. If the liquid between the two ends of the tester allows the electric current to pass, the circuit of the tester becomes complete and the bulb glows. If the liquid does not allow the current to pass, the circuit of the tester is not complete and the bulb does not glow.

In some cases though the liquid allows the electric current to pass through, the bulb does not glow. Then the bulb and the cells connected to the circuit should be checked and should be replaced if required.



S No
Compass needle shows deflection yes/no
Good Conductors/
Poor Conductors
Lemon Juice
Good Conductor
Tap Water
Vegetable Oil

Most liquids that conduct electricity are solutions of acids, bases and salts.

Chemical Effect and Electrolysis

When electric current is passed through acidified water, water molecules split into hydrogen and oxygen.

The two metal rods shown in the diagram are called electrodes.

This type of effect produced by electricity is called the chemical effect and the process is termed as electrolysis.

Can we use pure water in the place of acidified water? Find out.



Writing with electricity using chemical effect.

Things required:

  • KI (potassium iodide) salt solution

  • starch solution

  • a metal sheet

  • a paper napkin

  • a battery and

  • copper wire

  • crocodile clips


  • Take KI salt solution in a beaker. 

  • Connect the metal sheet to the negative end of the battery. 

  • Add a few drops of starch solution to it. 

  • Soak a piece of paper napkin in the KI solution in the beaker and place it on the metal sheet. 

  • Connect another wire to the positive terminal of the battery. 

  • Now write with this positive wire on the paper napkin.


Electrical energy can be used to plate one metal in a thin layer onto another metal. This is called electroplating.

What to use

Dilute solution of copper sulphate, copper electrode, object to be plated with copper (try objects such as buttons that are made of different metals, steel works well), wires, globe, switch, power source (about 1.5–3 V), goggles.

What to do?

  • Set up the apparatus as shown


  • To plate with copper the copper solution has to be very dilute: just a pale blue colour. Plating must be done slowly. 

  • Plate a variety of objects. 

  • You may need to refer to a textbook or other resources to answer the following questions:

    • Until recently, which metal was plated onto many parts of cars?

    • If you were restoring an old metal machine that was made before 1930, and it had to be re-plated, what metal should you ask for (nickel or chrome)? 

    • Why are metal objects often electroplated?

Use of chemical effect for silver and gold plating:

This type of plating is done to deposit a thin layer of gold or silver on surface of other metal, most often copper. It gives a gold or silver finish to the artificial jewellery and ornaments.     


Silver Plated Articles


Gold Plated Articles

Did you know?

  1. Electroplating is widely used in industry for coating metal objects with a thin layer of a different metal. For example, chromium plating is done on many objects such as car parts, bath taps, kitchen gas burners, bicycle handlebars, wheel rims and many others.
  2. Tin cans used for storing food are made by electroplating tin onto iron. Thus, food does not come into contact with iron and is protected from getting spoilt.
  3. Iron is used in bridges and automobiles to provide strength. However, iron tends to corrode and rust. So, a coating of Zinc is deposited on iron to protect it from corrosion and rusting.

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