States of Matter PDF

1.3 States of Matter 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. A sponge has minute holes, in which air is trapped, when we press it, the air is expel...

1.3 States of Matter 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. A sponge has minute holes, in which air is trapped, when we press it, the air is expelled out and we are able to compress it. Observe different types of matter around you. What are its different states? We can see that matter around us exists in three different states– solid, liquid and gas. These states of matter arise due to the variation in the characteristics of the particles of matter. Now, let us study about the properties of these three states of matter in detail. 1.3.1 THE SOLID STATE 1.3.2 THE LIQUID STATE Activity _____________ 1.9 Activity _____________ 1.10 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 Collect the following: (a) water, cooking oil, milk, juice, a cold drink. (b) containers of different shapes. Put a 50 mL mark on these containers using a measuring cylinder from the laboratory. What will happen if these liquids are spilt on the floor? Measure 50 mL of any one liquid and transfer it into different containers one by one. Does the volume remain the same? Does the shape of the liquid remain the same ? When you pour the liquid from one container into another, does it flow easily? We observe that liquids have no fixed shape but have a fixed volume. They take up the shape of the container in which they are kept. Liquids flow and change shape, so they are not rigid but can be called fluid. Refer to activities 1.4 and 1.5 where we saw that solids and liquids can diffuse into liquids. The gases from the atmosphere diffuse and dissolve in water. These gases, especially oxygen and carbon dioxide, are essential for the survival of aquatic animals and plants. All living creatures need to breathe for survival. The aquatic animals can breathe under water due to the presence of dissolved oxygen in water. Thus, we may conclude that solids, liquids and gases can diffuse into liquids. The rate of diffusion of liquids is 4 SCIENCE Rationalised 2023-24