Question on Refraction on diff. Substances

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In summary, the speaker has been working on a science fair project and is stuck on a particular part of their lab involving the angle of refraction of 5 different liquids. After analyzing the data, they discovered a surprising 'broken' relationship between density and angle of refraction. They concluded that the angle of refraction is closely associated with optical density, but this link is not always consistent and can vary depending on the substance. The speaker believes that this is due to the unique molecular structure of each substance affecting the way it interacts with photons. They are seeking help in understanding how and why this molecular structure affects light refraction. Some suggestions include looking at equations connecting permitivity near atoms, considering the "gold foil" experiment, and understanding
  • #1
!Live_4Ever!
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I have been doing a science fair project, *As some of you might have noticed by my previous posts* and I am TOTALLY stuck on this part of my lab.


So this is basically what happened while I was trying to find out the angle of refraciton of 5 different liquids:
After analysis of the data, it was surprising to discover that there was a ‘broken’ relationship between density and angle of refraction of a liquid. I also figured out that the angle of refraction can be associated closely to optical density and in general, the more optically dense a material is, the more the light will bend towards the normal meaning a smaller angle of refraction. Also, the angle of refraction usually increases as density decreases but this rule doesn’t apply to some substances. This leads to say that an atom’s ability to absorb electromagnetic waves for a length of time was not necessarily determined by the density of that liquid. I have ascertained that light refraction is a microscopic electromagnetic phenomenon, not a macroscopic mechanical phenomenon. This means that the reasoning why density does not affect the angle of refraction is in the fundamental functionality of molecules, and is not to be simply assumed by our everyday life intuition.

So what I concluded is that optical density of a substance correlates to the speed at which photons propagate through it. Because the molecular structure of every substance is unique, the way in which that structure interacts with the photons is also unique. This statement can ultimately conclude that the molecular structure of a substance determines its optical density, thereby determining its angle of refraction.

I have no idea how or why the molecular structure of every substance affect light refraction...

Can anyone help me out here?

Thanks in advance :-)
 
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  • #2
I definitely can't tell you for sure, but maybe my thoughts could help point out a direction you may not have thought of?

The optical density of the substance is very likely proportional to k (kappa) which modifies epsilon not (permitivity through free space). An optically dense material obviously is not able to pass EM waves nearly as well as an ideal system. There could be equations out there to help you connect the permitivity near atoms?

Also, the other idea I came up with is maybe it is similar to the "gold foil" experiment. If you are unfamiliar, it was what found that atoms are mostly empty space by shooting alpha particles through gold foil. When the particles got near the nucleus, it would cause them to be deflected. This one seems to be little more out there, but maybe it gets you thinking in the right direction?

Next, I know that the optical density also determines the speed of light within it. The idea could be proposed that since it is able to slow down the particle form of the wave, it is putting a significant force on the particles that when the beam enters the substance acts either perpendicular or parallel to the normal line and causes a bend in refraction.

Okay, lastly, it can be similar to current across a wire. Electron drift, vs total speed, etc.

Other than that, i have no idea. I'm sure someone out there knows the answer but you also have to consider the fact that physics, while you get smaller and smaller, does not necessarily mean you are getting closer. For example, the molecule of water does not explain the whirlpool. The electron drift idea is an excellent example because sometimes the answer is actually based in emergent phenomena rather than a single particle or property.
 
  • #3


It sounds like you have made some interesting observations in your science fair project! Refraction is definitely a complex topic and it can be challenging to understand all the factors that affect it. The relationship between density and angle of refraction is not always straightforward, as you have discovered.

The reason for this is that refraction is not just determined by density, but also by the optical properties of a substance. These properties are affected by the molecular structure of the substance. Different substances have different arrangements of atoms and molecules, which can affect how they interact with light.

For example, a substance with a highly ordered molecular structure, like a crystal, will have a different refractive index compared to a substance with a more disordered structure, like a liquid. This is because the ordered structure of the crystal allows for more efficient interaction with light, resulting in a higher refractive index.

Additionally, the chemical composition of a substance also plays a role in refraction. Different types of molecules behave differently when exposed to light, which can affect the overall optical properties of the substance.

So, in summary, the molecular structure and composition of a substance determine its optical density, which in turn affects its angle of refraction. I hope this helps to clarify things for you and good luck with your project!
 

1. What is refraction?

Refraction is the bending of light as it passes through different substances, such as air, water, or glass. This occurs because light travels at different speeds in different mediums.

2. How does refraction work?

Refraction occurs because light changes speed when it moves from one medium to another. This change in speed causes the light to bend, which is why objects appear distorted when viewed through different substances.

3. What factors affect refraction?

The main factor that affects refraction is the change in speed of light as it moves from one medium to another. The angle at which the light enters the substance also plays a role in refraction.

4. How is refraction measured?

Refraction is measured using a value called the refractive index, which is the ratio of the speed of light in a vacuum to the speed of light in a specific medium. This value is typically denoted by the symbol "n".

5. What are some real-life applications of refraction?

Refraction has many practical applications in our daily lives. Some examples include eyeglasses and contact lenses, which use refraction to correct vision problems, and cameras and telescopes, which use lenses to manipulate light and create images.

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