<section>
<h2 class="title">Electrical conductors, semi-conductors and insulators</h2>
<div class="ns-school-emp">
<h3>Definition: Electrical conductor</h3>
<div class="ns-school-defn">
<p>An electrical conductor is a substance that allows an electrical current to pass through it.</p>
</div>
</div>
<p>Electrical conductors are usually metals. <em>Copper</em> is one of the best electrical conductors, and this is why it is used to make conducting wire. In reality, <em>silver</em> actually has an even higher electrical conductivity than copper, but <a data-lesson="isolation-of-silver" data-subject="chemistry" data-tutorial="transition-metals" href="https://app.ulearngo.com/chemistry/transition-metals/isolation-of-silver">silver</a> is too expensive to use.</p>
<p>In the overhead power lines that we see above us, <em>aluminium</em> is used. The aluminium usually surrounds a steel core which adds makes it stronger so that it doesn't break when it is stretched across distances. Sometimes gold is used to make wire because it is very resistant to <a data-lesson="surface-area-and-reaction-rates" data-subject="chemistry" data-tutorial="energy-and-chemical-reactions" href="https://app.ulearngo.com/chemistry/energy-and-chemical-reactions/surface-area-and-reaction-rates">surface</a> corrosion. <em>Corrosion</em> is when a material starts to deteriorate because of its <a data-lesson="reactions-2" data-subject="chemistry" data-tutorial="metals-metalloids-nonmetals" href="https://app.ulearngo.com/chemistry/metals-metalloids-nonmetals/reactions-2">reactions</a> with <a data-lesson="occurrence-preparation-and-compounds-of-oxygen" data-subject="chemistry" data-tutorial="metals-metalloids-nonmetals" href="https://app.ulearngo.com/chemistry/metals-metalloids-nonmetals/occurrence-preparation-and-compounds-of-oxygen">oxygen</a> and <a data-lesson="unique-properties-of-water" data-subject="chemistry" data-tutorial="states-of-matter" href="https://app.ulearngo.com/chemistry/states-of-matter/unique-properties-of-water">water</a> in the air.</p>
<h3><strong>Power lines</strong></h3>
<a href="https://data.ulearngo.com/assets/d7c4ae64-6106-4c7c-9bc1-b55e26d9373f"><img alt="power_lines_motumboe" class="size-full wp-image-151132 alignnone" height="500" src="https://data.ulearngo.com/assets/d7c4ae64-6106-4c7c-9bc1-b55e26d9373f" width="316"/></a><br/>
<div class="ns-school-emp">
<h3>Definition: Insulators</h3>
<div class="ns-school-defn">
<p>An insulator is a non-conducting material that does not carry any charge.</p>
</div>
</div>
<p>Examples of insulators are plastic and wood. <strong>Semi-conductors</strong> behave like insulators when they are cold, and like conductors when they are hot. The <a data-lesson="elements" data-subject="chemistry" data-tutorial="classification-of-matter" href="https://app.ulearngo.com/chemistry/classification-of-matter/elements">elements</a> <a data-lesson="occurrence-preparation-and-compounds-of-boron-and-silicon" data-subject="chemistry" data-tutorial="metals-metalloids-nonmetals" href="https://app.ulearngo.com/chemistry/metals-metalloids-nonmetals/occurrence-preparation-and-compounds-of-boron-and-silicon">silicon</a> and germanium are examples of semi-conductors.</p>
<div class="ns-school-emp">
<h2>Optional Experiment: Electrical conductivity</h2>
<div class="ns-school-defn">
<section class="activity">
<h3>Aim</h3>
<p>To investigate the electrical conductivity of a <a data-lesson="atomic-and-atomic-mass-number" data-subject="chemistry" data-tutorial="chemistry-essential-ideas" href="https://app.ulearngo.com/chemistry/chemistry-essential-ideas/atomic-and-atomic-mass-number">number</a> of substances</p>
</section>
<section class="activity">
<h3>Apparatus</h3>
<ul>
<li>
<p>two or three cells</p>
</li>
<li>
<p>light bulb</p>
</li>
<li>
<p>crocodile clips</p>
</li>
<li>
<p>wire leads</p>
</li>
<li>
<p>a selection of <a data-lesson="reaction-rates-in-analysis-test-strips-for-urinalysis" data-subject="chemistry" data-tutorial="chemical-kinetics" href="https://app.ulearngo.com/chemistry/chemical-kinetics/reaction-rates-in-analysis-test-strips-for-urinalysis">test</a> substances (e.g. a piece of plastic, aluminium can, metal pencil sharpener, magnet, wood, chalk, cloth).</p>
</li>
</ul>
<a href="https://data.ulearngo.com/assets/0c3a5282-07c3-4589-ab60-f3b8831f0d98"><img alt="" class="size-full wp-image-151135 alignnone" height="394" src="https://data.ulearngo.com/assets/0c3a5282-07c3-4589-ab60-f3b8831f0d98" width="542"/></a></section>
<section class="activity">
<h3>Method</h3>
<ol>
<li>
<p>Set up the circuit as shown above, so that the test substance is held between the two crocodile clips. The wire leads should be connected to the cells and the light bulb should also be connected into the circuit.</p>
</li>
<li>
<p>Place the test substances one by one between the crocodile clips and see what happens to the light bulb. If the light bulb shines it means that current is flowing and the substance you are testing is an <strong>electrical conductor</strong>.</p>
</li>
</ol>
</section>
<section class="activity">
<h3>Results</h3>
<p>Record your results in the table below:</p>
<div>
<table>
<tbody>
<tr>
<td>
<p><strong>Test substance</strong></p>
</td>
<td>
<p><strong>Metal/non-metal</strong></p>
</td>
<td>
<p><strong>Does the light bulb glow?</strong></p>
</td>
<td>
<p><strong>Conductor or insulator</strong></p>
</td>
</tr>
<tr>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
</tr>
<tr>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
</tr>
<tr>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
</tr>
<tr>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
</tr>
</tbody>
</table>
</div>
</section>
<section class="activity">
<h3>Conclusions</h3>
<p>In the substances that were tested, the metals were able to conduct electricity and the <a data-lesson="non-metals" data-subject="chemistry" data-tutorial="classification-of-matter" href="https://app.ulearngo.com/chemistry/classification-of-matter/non-metals">non-metals</a> were not. Metals are good electrical conductors and non-metals are not.</p>
</section>
</div>
</div>
<div class="note visit">
<h3>Optional Video: PhET Primer: Circuit Construction Kit</h3>
<p><a href="http://phet.colorado.edu/en/simulation/circuit-construction-kit-dc">PhET Circuit Construction Kit Simulation</a></p>
<iframe allowfullscreen="allowfullscreen" frameborder="0" height="360" src="https://www.youtube.com/embed/ILRuvmficdg?rel=0&amp;modestbranding=1&amp;cc_lang_pref=en&amp;cc_load_policy=1" width="640"><span class="mce_SELRES_start" data-mce-type="bookmark" style="display: inline-block; width: 0px; overflow: hidden; line-height: 0;">﻿</span></iframe></div>
</section>

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Electrical Conductivity of Substances

Chemistry generally explores the substances of which matter is composed, the investigation of their properties and reactions, and the use of such reactions to form new substances. 

Chemistry

Explore the arrangement of elements and learn about materials, mixtures, pure substances, and separation techniques, including chemical formulae and important concepts such as periods in the periodic table and chemical properties of groups.


Electrical Conductivity of Substances

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