We explain what reflection is in physics, differences with refraction and various examples. Also, what is a personal reflection.
What is reflection?
In physics, a reflection is called phenomenon of abrupt change of direction experienced by certain waves (such as light or sound), when coming into contact with the separating surface of two different and changing media, and that causes part of the waves to return to the medium from which they came.
More simply put, a portion of the waves are returned when they encounter the surface of a different medium, as happens when light hits a mirror, losing a good part of its energy. Thus, by studying the nature of the impacted surface, it is possible to predict the range of change in direction of the waves, applying simple trigonometric calculations.
In this way, there are two types of reflection:
- Regular or specular reflection. It occurs when the impacted surface is polished and regular, and the waves undergo a change in direction without changing the medium of propagation.
- diffuse reflection. It occurs when the impacted surface is rough or irregular, and therefore the waves are not reflected in any direction, but rather diffuse.
Reflection is a very common optical phenomenon in daily life and well known since ancient times, the understanding of which has allowed the design of different technologies and applications in industry.
Reflection and refraction
The phenomenon of reflection is usually studied together with that of refraction, the latter being that, When passing from one medium of propagation to another slower, physical waves experience a certain margin of distortion which gives rise to different apparent phenomena.
This is what happens, for example, when we introduce a spoon into a glass of water, and we observe that the submerged portion and the portion in the air do not seem to coincide or are discontinuous: an optical illusion caused by the refraction of light in the water.
The refraction It is explained by the Snell-Descartes law which proposes a mathematical formula to calculate the angle of refraction of an electromagnetic wave when it penetrates from one medium to another that has a different refractive index, that is, different physical properties. This is because the speed of wave propagation is altered according to the medium they pass through.
In this way, Reflection and refraction are ways of altering the propagation of physical waves but while the first involves the “bounce” of waves on the surface of a medium, the second occurs when the waves actually penetrate the other medium and see their propagation capabilities altered.
Examples of light reflection
Some examples of light reflection are the following:
- The flashes of sunlight on the walls, when they impact the polished screen of a cell phone or a wristwatch.
- The possibility of seeing ourselves in a mirror whose highly polished surface allows the light beams to be returned to our eyes.
- The very existence of the colors It occurs due to reflection: white light impacts all things, and these only reflect certain wavelengths (the others are absorbed) that are captured by our eyes.
- The colors and the shapes seen on the surface of a soap bubble the result of the reflection of light on the delicate surface of the bubble.
personal reflection
There is another possible meaning of the word reflection that has nothing to do with physics, but that comes from the same etymological root: the Latin word you reflectcomposed of re (“backwards”) and flectere (“double” or “deviate”). Thus, “reflecting” would be “doubling back,” and in a figurative sense, involves looking back in time, that is, thinking about what we experienced to see what already happened again, that is, to reflect.
Obviously, a reflection is not necessarily a review of the past, but can also consist of an anticipation of the future or an investigation of the present but in any case it always has the meaning of a deep thought or a review (that is, “seeing again”) of things in any area.
Continue with: Electromagnetic spectrum
References
- “Reflection (physics)” on Wikipedia.
- “Refraction” on Wikipedia.
- “Reflection” in the Dictionary of the language of the Royal Spanish Academy.
- “Reflect” in the Dictionary of the language of the Royal Spanish Academy.
- “Reflection and refraction of light” in Physics Lab.
- “Reflection (physics)” in The Encyclopaedia Britannica.
