Particulate Nature: Matter state I

Historically, matter state is distinguished based on qualitative differences in its ontological properties. A solid is a state in which a substance maintains a fixed volume and shape; a liquid is a state in which a substance adapts to the shape of its container but the volume changes only slightly; a gas is a state in which a substance expands to occupy the volume and shape of its container.









Matter, the material that makes up the observable universe, together with energy, forms the basis of all objective phenomena. At the most basic level, matter consists of elementary particles called quarks and leptons (including the elementary particles of electrons). Quarks combine into protons and neutrons,and together with electrons form atoms of periodic table elements, such as hydrogen, oxygen and iron. Atoms can further bind constituent molecules, such as water molecules, H2O. Large clumps of atoms or molecules constitute the main substance of daily life.

Matter state



Solid particles are tightly stacked together. The force between the particles is strong enough that the particles cannot move freely; they can only vibrate. Therefore, the solid has a stable, determined shape and a determined volume. Solids can only change shape under the action of force, just like when crushing or cutting. In a crystalline solid, the particles are packaged in a regular and orderly repeating pattern. There are many different crystal structures, and the same substance can have more than one structure.

For example, iron has a body-centered cubic structure at a temperature below 912°C, and a face-centered cubic structure between 912 and 1394°C. Ice has fifteen known crystal structures, each of which exists at different temperatures and pressures. Solids can be converted to liquids by melting, and liquids can be converted to solids by freezing. Solids can also be directly converted into gases through a process called sublimation.


A liquid is a fluid that conforms to the shape of its container, but maintains an almost constant volume regardless of pressure. If the temperature and pressure are constant, the volume is determined (not changed). When a solid is heated above its melting point, it becomes a liquid because the pressure is higher than the triple point of the substance. Intermolecular (or atom-to-atom or ion-to-ion) forces are still important, but the molecules have enough energy to move around, which makes the structure move.

This means that the shape of the liquid is not determined, but in line with the shape of its container. Its volume is usually larger than its corresponding solid (water is a well-known exception to this rule). The maximum temperature at which a particular liquid can exist is called its critical temperature. The liquid can be converted into a gas by heating to the boiling point of the substance at a constant pressure or by lowering the pressure at a constant temperature. The process of converting this liquid into a gas is called evaporation.


Gas molecules have very weak bonds or no bonds at all, so they can move freely and quickly. Therefore, the gas will not only conform to the shape of its container, but also expand to completely fill the container. Gas molecules have sufficient kinetic energy, the impact of intermolecular forces is small (zero for an ideal gas), and they are very far apart from each other; the typical distance between adjacent molecules is much larger than the size of the molecule itself.

A gas at a temperature below its critical temperature can also be called a vapor. Steam can be liquefied by compression without cooling. It can also exist in balance with a liquid (or solid), in which case the gas pressure is equal to the vapor pressure of the liquid (or solid).


The experimental evidence of the atomic nature of matter is seen in the Brownian Movement. It was named after the Biologist Robert Brown after his discovery when he observed tiny pollen grains suspending in water under a microscope he observed the grains moved in a zig zag manner on the perfectly still water surface. In essence the pollen grains were knocked about by the movement of water molecules.

The second is seen in the analysis of chemical reactions seen in the law of definite proportions which states that when two or more elements combine to form a compound they do so in same property by weight.

The third is in the processes of diffusion which is the movement of particles or molecules from a region of higher concentration to a region of lower concentration. An example is observed in a room where perfume has been sprayed.



Brownian motion, also known as Brownian motion, any variety of physical phenomena, some of which constantly occur in small, random fluctuations in quantity. If there are many particles affected by Brownian motion in a given medium, and there is no preferred direction of stochastic oscillation, then over a period of time, the particles will tend to be evenly distributed throughout the medium. The physical process of stable diffusion of substances from high-concentration areas to low-concentration areas is called diffusion.


An atom consists of three elementary particles: protons, electrons, and neutrons. The nucleus (center) of an atom contains protons (positively charged) and neutrons (non-charged). The outermost region of an atom is called an electron shell and contains electrons (negatively charged). Atoms have different properties according to the arrangement and number of their elementary particles.

An Atom

Atomic Structure


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