The physical and chemical phenomena that happen around us have been a source of interest since ancient times, and important civilizations such as the Egyptians, the Chinese and especially the ancient Greeks paid special attention to them, in order to describe and interpret them.
The difference between physical and chemical phenomena lies in determining whether or not there is a change in the nature or characteristic properties of the elements involved:
- Physical phenomena. There are no changes in the composition of substances, the molecules do not vary. For example: hail, crumple a paper, stretch a spring.
- Chemical phenomena. Yes, there are changes and eventually new substances appear. For example: salinization of soils, jams, photosynthesis.
Furthermore, in physical phenomena, substances can generally return to their original state, while this is not common in chemical-type phenomena.
Dangerous phenomena
Many natural physical phenomena they are devastating to humans and societies in general, and countries often have to put in place complex relief systems to help victims of natural disasters.
At the same time, they must spend many material resources so that entire cities recover from the damages caused by natural events such as earthquakes, floods or tsunamis.
Also some chemical phenomena suddenly become natural disasters: forest fires are a clear example of this.
Benefits of physical and chemical phenomena
Chemical phenomena, on the other hand, have made it possible to develop a wide range of products that humans use in different ways.
The obtaining alcoholic beverages from fruits or grains and from cheeses it is based on the chemical process of fermentation. Before digital photography existed, photos were obtained by a process that involved the use of a silver salt.
The light from space and the light that is reflected off the bodies was directed through the set of lenses and fell on a photographic film. The energy of the photons caused a chemical reaction in that silver salt (bromide or iodide).
Many physical phenomena are also the basis of the functioning of a number of instruments or machines that make people’s lives easier.
Let’s think about the levers, pulleys, rigging and other mechanical systems, which have meant and still are a huge help to move heavy objects, for example.
Or in all optical instruments that we have today, from simple glasses and magnifying glasses to more complex ones, such as microscopes and telescopes, which allow us to see very small or very distant objects, respectively, in enormous detail.
All of them take advantage of physical phenomena such as diffraction, reflection or refraction of light.
Examples of everyday physical and chemical phenomena
Some examples of physical or chemical phenomena are given below.
Physical:
- Water condensation on a window
- Apple falling from the tree
- Hail
- Preparation of an infusion
- Volcanic eruptions
- Preparation of ice cubes from water
- Crumple a paper
- Stretch a spring
Chemicals:
- Corrosion of metals
- Digestion of food in the human body
- Water purifiers
- Leavened bread
- Soil salinization
- Fires
- Operation of a battery
- Car batteries
- Pickles
- Jams
- Preservation of olives in brine
- Photosynthesis