Physics/Science of Light (PART 7)

Physics/Science of Light

(How you could implement it + create dramatic compelling art scenes)

Translucent Properties

We've talked a bit about reflection, when light strikes the particles of any given surface and gets deflected by it in some ways; however, this is what happens when light interacts with solid surfaces.

In reality, matter is generally not made up of extremely compressed that cause them to form dense solids that prohibit any light to pass through, in fact, most atoms are loosely spaced.Enormous vast distance exists between each atom so the possibility of light passing through any particular medium is high. There are some surfaces like metal (very dense materials) where it becomes very unlikely for the light pass through. But in most surfaces, under normal circumstances, the likelihood of some light passing through them exists.

The minimal density of transparent materials such as liquids and gases allow a high possibility of light passing through them.

The loosely spaced structure of the atoms/molecules which make up liquid the freedom to move around a lot more. This is also true with gases, except the structure of the atoms which make up gases is much more loose.

Ok, something that we haven't talked about before, and that is SCATTERING.

We come across scattering when we refer to diffuse reflection, but scattering in physics is a different matter. Scattering has to do with the properties of light and how it interacts with atoms.

An atom and a light wave have a variety of ways they can interact. Let's take a quick look at the traditional model of an atom; the nucleus along with the electrons are part of the structure.

When light (travelling very quickly at about 186'000 m/s) comes in and strikes the atom, the electrons absorb the energy from the impact and pushes it out to a higher energy level.

The electrons become more agitated. And when the higher energy levels become unsustainable by the atom, the atom absorbs some of the wavelength and this causes the atom to vibrate. As for the remaining electrons, they jump down to a lower energy level and shoot light out back again.

For all intensive purposes, the light just basically bounced off the atom, with the exception of the lost light.

There are other phenomena that could happen.

There exists atoms that are more stable and sustainable than others and these particular atoms have atoms that are structured in a way that aren't as prone to respond to light. So if light were to come in and hits these atoms it may even bounce them off to a higher energy level,but the net result is that the light continues unaffected.

There will be some interactions when the electrons will capture the light, store it and release it later.

These variations of interactions occur based on quantum physics.

Back to scattering, another type of scattering is when light bounces off a surface and shoots in arbitrary directions.

Transparent surfaces might have lambertion and specular properties, but may include a few extra things underneath.

How does light interact with transparent surfaces?

Theres a variety of processes that occur when light interacts with transparent surfaces.

If we take a transparent ball for an example, the atoms scattered and spaced out make up the surface but if we were to look at the structure more closely at a microscopic level, we start to see the atoms along the curve are considerably compressed. That curve along the edges of the ball has a structure that is much more dense/thick than the rest of the ball. The density of that area proves more challenging for the light to pass through.

There is also an exponential growth in density the further along the curve.

As shown above, the first light (label the lines (light) with numbers) is more likely to pass through the transparent ball then 2nd light, and the 3rd light offers the least amount of probability of getting through (you might get some beams of light but generally it will have a hard time succeeding).

This is the process that occurs at a molecular level, but what we see in the overall appearance is the darkening of the outside edges along the ball.

(as seen in ball 4).

With the glass shown in the picture, it's easy to spot how the lightening effects appear along the edges of the glass cup against a dark background. Whereas the edges of the bottom portion of the cup is darker against the light background.

With the glass shown in the picture, it's easy to spot how the lightening effects appear along the edges of the glass cup against a dark background. Whereas the edges of the bottom portion of the cup is darker against the light background.