We must have noticed various substances in our surroundings. Do all substances look same? Observe ice cube, a glass of water and vapours over boiled water. Do all of them are same? No. They are different in their physical appearence. When ice cubes melt, they convert into water and after boiling water at high temperature, water converts into vapour state. All material or substances in our surrounding is known as “matter”.
Matter can be defined as the substance that has mass and occupies volume. So a grain of sand or water or ice cubes, all are matter. All matter is composed of small building blocks which are called as particles. The concept of matter was given by Greek philosophers Leucippus and Democritus. According to them, particles of matter are separated by empty spaces. Any change in the arrangement of particles causes changes in matter.
On the basis physical properties and chemical nature of particles, matter can be classified as solid, liquid and gases. The particles of matter have space between them and are continuous in motion. They have strong or weak attraction forces between them. Particles of matter possess kinetic energy that is responsible for their motion.
See the given image. It consists of some of the substances that can be easily observe in different states of matter. Like water (liquid state), sand (solid state), steam (gaseous state) etc.
Given picture shows water in three different states of matter. All these three states are convertible into each other by changing their surrounding slice temperature, pressure etc.
Some of the common examples of solid, liquid and gases are listed in below table.
| Solid Iodine
| Metals (iron)
|| Iodine solution
|| Iodine vapors |
All states of matter are composed of atoms, molecules, and/or ions whose show different behaviors. Gaseous particles are separated with large intermolecular space and have no regular arrangement. On the contrary, liquid are close together but have no regular arrangement. Unlike liquids, solid particles are tightly packed with a regular pattern.
Gaseous particles can move freely due to high kinetic energy whereas solid particles can only vibrate at their mean position due to strong intermolecular force attraction between particles. Liquid particles can move and take the shape of container. Due to some regular pattern, liquid and solid states of matter are often called as condensed phases.
The conversion of one state to another state of matter is called as phase transition. Usually temperature and pressure are major cause of phase transition. For example; conversion of solid to liquid by heating is called as melting. Similarly conversion of liquid state to gaseous state by heating is called as vaporization.
Some of the solid substances cannot convert liquid and directly change to gaseous state. They are known as sublime and this process is called as sublimation. Iodine, camphor are good examples of sublime substances.
Have a look of given picture. It explains the arrangement of particles in three state of matter. One can easily differentiate between three states by observing this picture. Let’s list some common properties of solids, liquids and gases which help to differentiate them from each other.
| Particles are rigid and very close to each other.
|| Particles are not rigid and have some space between them.
|| Particles are not rigid and have large intermolecular space between them.
| They have fixed shape as particles cannot move.
|| They do not have fixed shape and take shape of container.
|| They do not have fixed shape due to random movement of particles.
| They have fixed volume.
|| They also have fixed volume.
|| They do not have fixed volume.
Characteristics of Solids Liquids and Gases
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Let’s learn about few characteristics of different states of matter. Solid particles cannot move from one place to another therefore solids have fixed shape and do not flow. They cannot spread like gases but can be cut easily. On applying high temperature, usually solids convert to liquid state like conversion of ice cubes to water. Therefore cooling of liquids also turns them to liquid state.
Because of intermediate intermolecular space and attraction forces, liquids show some unique properties like flow, viscosity, surface tension etc. They take the shape of container and do not easy to hold. Heating of liquids changes them to gaseous state while cooling of them forms solids. Unlike solids, gaseous particles have high kinetic energy and have large intermolecular space between them. Therefore they show random movement.
Cooling of gases converts them to liquid then solid state. Gases are usually invisible and easily spread out. They can be compressed easily due to large intermolecular space between particles.