Solid State
Matter in solid state has a definite shape and definite volume.
Examples: Silver, copper, sand, sugar, gold, ice, wood, stone, book, needle, pencil, piece of thread, etc.
*Properties of Solids
(a) Solids have a definite shape and distinct boundaries: The solids have a fixed shape and distinct boundaries due to small inter particle distances and strong forces of attraction. e.g. when a pen is put in different containers, it does not change its shape.
However, when sugar and salt, are placed in different containers, they take up the shape of the containers, yet they (sugar & salt) are solids. This is because, the shape of individual sugar or salt crystal remains fixed whether we take it in our hand, or put in a jar or in plate. The highly ordered arrangement of constituent particles of a solid is called a lattice. This gives rise to a regular geometrical shape to the crystals.
(b) Solids possess rigidity: The solids have the tendency to maintain shape, when some outside force is applied (known as rigidity). They may break when dropped or hammered.
However some solids like rubber band, changes its shape when stretched under influence of force, but it regains its original position, when force is withdrawn. However, if excessive force is applied, rubber band breaks.
(c) Solids have a definite volume : Solids have a definite volume as they can not be compressed due to small inter particle distances.
However some solids like sponge can be easily compressed. This is because sponge has minute holes in which air is trapped so that when we press it, air is expelled and the sponge is compressed.
(d) Solids do not possess the property of diffusion :- The solids do not have the property of diffusion into other solids (i.e. the particles of two solids do not intermix). This is because the particles of solid do not move much from their positions due to small inter particle distances and strong forces of attraction.
However particles of some solids like chalk have diffused into other solids like blackboard. i.e. if we write something on blackboard with the chalk and leave it uncleaned for sometime, we will find that it becomes difficult to clean the board. This is because of diffusion of chalk particles in between the particles of blackboard and hence it becomes difficult to rub them off.