Testing Solids and Liquids for Electrical Conductivity

Any substance that electricity is able to move through is known as a conductor.  It is possible to set up tests that measure the conductivity levels of certain materials, whether they be liquids or solids.  A few simple materials are needed in order to carry out the tests:

*  A 6 or 9 volt battery
*  A three feet length of insulated copper wiring
*  Wire cutters 
*  Flashlight bulb
*  Paper clips
*  Small container for holding liquids

–  Testing solids for conductivity:

You need to cut three pieces of copper wiring – about 10 inches for each one.  An inch of insulation needs to be removed from both ends of each piece of wiring, so that the wire is exposed.  Taking one 10 inch piece of wire, wrap one of the exposed ends firmly around one of the battery terminals then attach the opposite end of the wire to the base of the flashlight bulb, taking care to secure it properly.  Attach the second piece of copper wiring to the other battery terminal.  The third piece of wiring needs to be wound around the base of the flashlight bulb, close to where the first wire has been attached.  It is important to have all connections tied with bare copper wiring in order to conduct the electrical circuit.  To test, take the spare ends (non-attached) of the second and third pieces of wiring and touch them together.  The bulb should light up as a result. 

Now it is a very simple process in order to test any solid for electrical conductivity – you just need to touch the object with the spare copper wiring ends to complete the electric current.  If the solid is very conductive, the light should glow brightly – the brighter the light, the more electrically conductive the solid is.  If there is no light at all, then test the circuit carefully before concluding that the particular object is not very, or not at all, conductive.

–  Testing liquids for conductivity:

Using the same wired/ bulb tester you’ve constructed, first take two paper clips and attach them to the free ends of the second and third pieces of copper wiring.  You then need to secure the paper clips to the sides of a cup, or other small container in order to carry out the test.  Liquids to be tested should be poured, only one at a time, in to the container so that the liquid level touches the attached paper clips.  If the light bulb glows then the liquid being tested is an electrical conductor – the brighter the light, the more conductive the liquid is.  Any bubbling observed around the paper clips, indicates that a milder conductivity is taking place.

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