THE SOLID STATE
• Collect the following articles— a pen, a book, a needle and a piece of wooden stick.
• Sketch the shape of the above articles in your notebook by moving a pencil around them.
• Do all these have a definite shape, distinct boundaries and a fixed volume?
• What happens if they are hammered, pulled or dropped?
• Are these capable of diffusing into each other?
• Try compressing them by applying force. Are you able to compress them?
All the above are examples of solids. We can observe that all these have a definite shape, distinct boundaries and fixed volumes, that is, have negligible compressibility. Solids have a tendency to maintain their shape when subjected to outside force. Solids may break under force but it is difficult to change their shape, so they are rigid.
Consider the following:
(a) What about a rubber band, can it change its shape on stretching? Is it a solid?
(b) What about sugar and salt? When kept in different jars these take the shape of the jar. Are they solid?
(c) What about a sponge? It is a solid yet we are able to compress it. Why?
All the above are solids as:
• A rubber band changes shape under force and regains the same shape when the force is removed. If excessive force is applied, it breaks.
• The shape of each individual sugar or salt crystal remains fixed, whether we take it in our hand, put it in a plate or in a jar.
Shaalaa.com | Matter Part 2 (States of Matter)
'A substance has a definite shape as well as a definite volume'. Which physical state is represented by this statement?