They refer not to the element itself, but to different densities of matter and different characteristics that they possess. The mahabhutas represent the physical qualities, energetic properties and biological functions related with the the given element. English equivalents are used to simplify the meaning of the panchamahabhutas.
The density of the 5 elements increases from ether to air, to fire, to water, to earth. The 5 elements originate from the subtle and all pervasive universal consciousness. Ether is the most subtle of the 5 elements and has its origin from consciousness itself, even though less subtle than consciousness or spirit. In this same way, air has its origin from ether and is less subtle and pervasive than ether. Fire originates from air and is more dense than air. Water has its origin from fire and is more dense than fire. Earth has its origin from water and is the most dense of the 5 elements.
Every animate and inanimate being is made up of atoms, the 5 mahabutas can be explained with the example of an atom:
Aakash (space component) is the space which the protons and neutrons occupy as well as the space in which the electrons revolve.
Vayu (air component) represents the force of movement of the electrons around the nucleus.
Agni (fire component) represents the latent energy in an atom as well as the released energy when an atom is broken down.
Jala (water component) gives the force of cohesion that allow the protons, neutrons and electrons to remain attracted towards each other.
Prithvi (earth component) contributes the solid portion of the atom (i.e. the electrons, protons, and neutrons).
Akasha (ether) is ever present; it is the space in which everything exists and acts. Aakash is fine, subtle, soft, light, porous, and smooth in quality. In the body aakash is found where there is empty space such as in the tubes and channels (srotas) of the body. Such empty spaces are found in blood and lymph vessels, openings, pores, and the intestinal tract. Aakash also contributes the sounds of the heart, lungs, intestines, and swallowing.
Aakash is space; all sound is transmitted through space and is related to the sense of hearing. The ear is the sense organ of hearing and since sound is produced through means of the vocal cords and mouth these are considered to be the organ of action related to the sense of hearing. Vishuddha chakra is located in the area of the throat and is directly related to the ether element and the tanmatra of sound.
Vayu (air) is the gaseous form of matter. It is mobile, dynamic, light, cold,rough, fine, subtle, dry and exists without form. All empty spaces are filled with air. Air flows freely throughout the body, controls breathing, feeds the cells with oxygen and helps to give movement to biological functions.
Air relates to the sense of touch, therefore skin is the related sense organ and the hand is the organ of action. The air element corresponds to anahata chakra, also called the heart chakra. Vayu is related with the actions of giving, and receiving and is displayed in it’s correspondence with the hands and anahata chakra.
Agni (fire) is hot, sharp, subtle, fine, light, slightly sticky, and radiant in quality. Agni is found in the heat and energy of the body. Fire exists in all metabolic processes and chemical reactions. Fire is the transformational force; it promotes appetite, digestion and metabolism converting food to energy, creates thought processes and bodily impulses. Agni is also responsible for providing luster, radiance, and color for the body.
Fire relates to vision because of its qualities of heat, light, and color. The eye is the sense organ of sight. Agni’s ability to give direction and impulse relates it to the feet as it’s organ of action. Manipura chakra, the navel chakra corresponds with the fire element.
Jala (water) is liquid, sticky, cold, soft, compact, heavy, and moist in quality. Water constitutes the liquids of the body and represents the force of cohesion, as well as the abilities to attract and to change that are associated with water. This element provides the bodily fluids such as urine, plasma, lymph, and makes up most of our bodily weight. The bodily fluids move between the cells and through the vessels of the body carrying nutrients, wastes, antibodies and hormones.
Water is related to the perception of taste and it’s sense organ is the tongue. The related sense organ is the genitals which are very closely linked in function to the tongue. Without water neither the tongue nor genitals can function properly. Svadhistana chakra is located in the area of the genitals and is attuned with the water energy.
Prithvi (earth) represents the solid state of matter. Earth is heavy, hard, stable, compact, rigid, unctuous, and dense in quality. Bones, teeth, muscles, fat, and the structure of the different organs are derived from the earth element.
Earth is related to the sense of smell. The nose is the sense organ through which we perceive smell. The organs of action is the anus which allow us to excrete matter back to the earth. Muladhara chakra, also called the root chakra is located outside the body in the area of the perineum. The root chakra is our connection to the earth, giving us stability in the body and the mind.