<h3 class="side-heading"><strong>Question 1:</strong></h3>
<p><strong>How Will You Separate Solids (Dirt or Salt) From the Liquid (Water)?</strong></p>
<p><strong>Answer:</strong></p>
<p>The following methods can be used to separate dirt or salt from water:</p>
<ul>
<li>Salt can be separated from water by the process of evaporation.</li>
<li>Dirt can be separated by the process of sedimentation (settling of dirt particles at the base of the container) and decantation.</li>
<li>Alum can be mixed with water to increase the rate of sedimentation and separate clear water.</li>
</ul>
<h3 class="side-heading">&nbsp;</h3>
<h3 class="side-heading"><strong>Question 2:</strong></h3>
<p><strong>Glass Is Fragile but Still Used to Make Windows on a Large Scale. Why Do You Think So?</strong></p>
<p><strong>Answer:</strong></p>
<p>Glass is used to make windows due to following reasons:</p>
<ul>
<li>It is cheaper than other materials.</li>
<li>It is transparent and allows light to pass through it.</li>
<li>It is convenient to clean the glass.</li>
</ul>
<h3 class="side-heading">&nbsp;</h3>
<h3 class="side-heading"><strong>Question 3:</strong></h3>
<p><strong>Switches in the Electric Boards Are Made of Plastic Instead of Wood. Why?</strong></p>
<div><strong>Answer:</strong>
<p>Though both wood and plastic are insulators, plastic is used to make electric switches due to the following reasons:</p>
<ul>
<li>Plastic is more durable than wood.</li>
<li>It can be heated and moulded into different shapes, unlike wood.</li>
<li>Thermosetting plastic used to make switches do not catch fire easily.</li>
<li>Plastic does not absorb water.</li>
</ul>
</div>

Here students will come to know about the properties of materials.

Properties of Materials

Question 1:

Question 2:

Question 3: