We explain what physical phenomena are, their characteristics, what types exist and various examples. In addition, chemical phenomena.
What are physical phenomena?
It is called physical phenomena or physical changes to the changes in the state of the material produced without altering the chemical composition of the same, since not involve any chemical reactions. In the latter they are distinguished, precisely, from chemical phenomena . They are mostly reversible.
Physical phenomena involve the set of forces that ordinarily affect matter, as well as its change of state of aggregation : liquid, solid, gas or plasma. They may also have to do with the mixture of substances, as long as they are heterogeneous mixtures, in which solvent and solute do not have any type of permanent molecular bond.
Characteristics of physical phenomena
Physical phenomena, in principle, are observable to the naked eye , given that the state of matter tends to change in a macroscopic manner. This is even more true for reversible physical changes.
However, in this type of phenomena the amount of matter is not altered , that is, the change does not imply a profound transformation of it, nor the creation or destruction of it, but simply the transit from one state to another, or from one structure to another.
Types of physical phenomena
The physical phenomena can be different, depending on the origin they have, usually in some of the physical forces of the universe . That way, we can talk about:
- Movement . It occurs when a body changes its resting position and moves from one point to another, or when it alters its trajectory and acquires a new one. All this as an effect of some kind of force on him, be it gravity , the impact of some other body, etc. It is what happens when things fall to the ground, for example.
- Heat . It has to do with the level of energy present in a body, that is, the speed and intensity with which its particles are agitated. Objects with higher internal energy will havehigher temperatures , and those with lower energy, lower temperature. By adding heat to a body, it is possible to induce a change of state of aggregation, such as when we boil water and turn it into gas, or when we freeze water and make it solid.
- Light . Electromagnetic radiation from energy sources such as the sun , affects matter generating various phenomena. For example, the color of things is the result of light impacting objects and reflecting a single color among all those that make up the spectrum .
- Magnetism . Some metals (especially those linked to iron) have the ability to attract or repel other metals, due to their electronic configuration. These types of reactions do not alter the repelled or attracted metal, they simply reorganize the most superficial particles of their atoms .
- Electricity . Electricity and magnetism are very related, since they come from the properties of electrons in the atoms of matter. But electricity, unlike magnetism, can be transmitted through certain materials known as conductors . Electricity is nothing more than the difference in electrical potential between one point and another in matter, which generates an electronic displacement capable of becoming other forms of energy: heat, light, movement, etc. A simple example of this is lightning: violent compensation of electrical potential between the atmosphere and the ground .
- Sound . The rhythmic vibration of certain bodies is capable of generatingsound waves that are transmitted in the air or water , thus generating sounds perceptible by the human or animal ear. The properties of sound depend on the vibrating matter and the propagation medium of the waves. This is what happens when the bells of a church are ringing.
Examples of physical phenomena
Some simple examples of physical phenomena are changes in water states . In its natural state and at ordinary atmospheric pressure, water is liquid and transparent, just as it is when we drink it. If we add heat, heating it in a container, once it reaches 100 ° C the water will evaporate, converted into a gas (steam).
If, on the contrary, we remove heat by putting it in a freezer, once it reaches 0 ° C the water will start to crystallize and eventually become solid (ice). All these processes are reversible through the reverse mechanism: add or remove heat.
Physical phenomena and chemical phenomena
As we said initially, the difference between physical phenomena and chemical phenomena has to do with the type of change in matter. In the first case, it is a change of structure, of state, in which the substance remains chemically the same. For example, frozen water is still made up of hydrogen and oxygen.
Instead, chemical phenomena reorganize the molecular nature of matter , building and destroying atomic bonds and creating new substances. This is because a chemical reaction, usually irreversible, occurs in which substances totally different from the initial ones are obtained.
For example, metals that react with oxygen oxidize , losing some of their properties, without the recovery of oxygen, nor the transformed metal.