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Among the many classifications that can be made about bodies, one of the most common is the one that differentiates them according to the level of light that they allow to pass beyond their own position.
How is this explained?
Electrons are particles that are around the nucleus of atoms and have different energy levels. They can be excited by the photons that are the particles of light, assimilable with "energy packages". In this way, when photons reach an object, they penetrate its material and excite the electrons, trying to deliver energy in such a way that they pass (or "jump" as they say) of the electronic level.
The difference, precisely, lies in the moment in which the photons try to pass the energy: opaque objects succeed and, therefore, the photons are "consumed". The transfer of energy is what explains why objects do not let light pass through, but they get hotter the more intense this energy is: in this same sense, dark objects are more likely to absorb photons than light ones. On the contrary, when it comes to transparent objects, the jump they have to make to be absorbed is not possible and the photons go through the object in search of new electrons to excite.
The behavior of objects with respect to photons is not binomial and phenomena such as reflection of light (the change of direction that occurred at the separation surface) or refraction (the change in velocity when passing a material medium to another).
On the other hand, the condition of transparency and opacity depends in most cases on the energy (or frequency) of the light that falls on an object. Aluminum, for example, is opaque in the frequency range of visible light, but is completely transparent in the frequency of ultraviolet rays.
- See also: Conductive materials
Examples of transparent
Transparent bodies are those that let through almost all the light that falls on them. The intensity of the incident light is very similar to that transmitted and that explains why they are usually not so prone to heat up.
- Water in a liquid state.
- Glass
- Door glass
- Smooth plastic
- Cork glass
Examples of translucent
Translucent bodies are those that let in a little light, but not enough to see clearly what is behind them. They are in an intermediate level between transparent and opaque.
- Stained glass
- Frosted glass
- Onion paper'
- Diamonds
- Oil
- Drinks like whiskey
- Ice
- Some fabrics
Examples of opaque
Opaque objects are those that do not allow light to pass through and absorb all that they receive. Most of the objects with which people are in contact, especially those made by man, are of this type because the materials with which they are made are also.
- Metal
- Plastic
- Wood
- Iron
- Cardboard
- Tablecloth
- Cement
- Continue with: Temperature conversion
