Visible light is a very narrow range of wavelengths and frequencies in the electromagnetic spectrum that humans can see. It is the small portion of electromagnetic radiation that is visible to the human eye.
Visible light is the only type of radiation that we can perceive. When light reflects off objects and into our eyes, we see an image.
Wavelengths consisted in the color spectrum vary in size. Different wavelengths of visible light appear as separate colors, which is why you see a rainbow.
The wavelengths are mainly between 400 nano meters (nm) and 700 nm. Violet has the shortest wavelength, at around 380 nm. Red has the longest wavelength, reaching 700 nm.
A medium is the matter that a wave travels through.
The three different mediums are transparent, translucent, and opaque.
Materials that are capable of allowing light to travel through them without any disturbance are known as transparent mediums. When air strikes a transparent surface, it is being transmitted. This means that you can see the light very clearly. A glass door is a good example of an object capable of transmitting light, because it is transparent.
When you pick up a plastic container, it appears to be fogged up, and frosty. Materials that can only transmit some light are called translucent. Translucent mediums absorb some of the light that strikes them, but not enough to enable you see the image on the other side. A frosty window is translucent, as well as a plastic milk container.
When light is completely absorbed by an object, that means that the surface it has come in contact with is opaque. Opaque materials block all light from transmitting, making it impossible for light to pass through. A wooden door is opaque.
Light behaves differently towards different mediums. Visible light waves can either be transmitted, reflected, absorbed, diffracted, or scattered, depending on the composition of the object.
When visible light waves come into contact with water, they are diffracted, or bent, in a separate direction. This explains why the sun's reflection appears to scatter across the surface of water. When you look into a glass of water, you are most likely to see your own eyes staring back at you. This is caused by the visible light waves reflecting off of the water and back into your eyes, creating an image. So, water is capable of diffracting and reflecting!
The moment light comes into contact with wood, it is completely absorbed and blocked from going through the other side. This occurs because wood has an opaque medium, and the matter is to dense to transmit any light.
When light strikes a mirror, it immediately bounces off the surface, reflecting back into our eyes. This is how we see ourselves when we look into a mirror. While water is capable of reflecting and diffracting, a mirror isn't capable of bending the rays of light that come into contact with it's surface.
People with color deficiency, or color blindness, perceive the world much differently than people with normal vision. This is caused by the lack of variations in wavelengths consisted in the electromagnetic spectrum.
The most common type of color blindness is duteranopia, or red-green color blindness. People with duteranoipa are incapable of telling the difference between red and green. While people with normal color vision can differentiate between red and green, people with duteranopia would be unable to spot a red apple in their lawn.