The particles in a solid are packed close together and locked into position, normally in a repeating pattern or structure. This is the reason that solids hold their shape and feel firm. As the particles are so close together, it is almost impossible to squeeze them closer together, making solids hard to compress. This does not mean that the particles in a solid are not moving however, as the particles still have some energy. The particles in a solid have just enough energy to vibrate in place.
Solids are described as having definite shape and definite volume as these two properties will not change.
When placed into a container, a solid will hold its shape and volume.
Examples of solids include: ice, cheese, bricks, wood, diamond and glass.
The States of Matter 