Refractive index of different liquids

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Discussion Overview

The discussion revolves around the refractive index of various liquids, including water, alcohol, syrup, and oil, as investigated through an experimental approach. Participants explore the relationship between refractive index and material properties, particularly density, while also considering broader implications of optical transparency across different wavelengths.

Discussion Character

  • Exploratory
  • Technical explanation
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • Peter notes that their experimental results indicate oil has a higher refractive index than water, while a sugar solution has a lower refractive index, challenging the assumption that refractive index correlates with density.
  • One participant emphasizes that optical density should not be conflated with mass/volume density, suggesting a distinction that may clarify Peter's observations.
  • Another participant raises the question of how different materials can be transparent to certain wavelengths while opaque to others, expressing curiosity about the nature of optical properties across the electromagnetic spectrum.
  • A later reply mentions the ionosphere as an example of a medium that is transparent to visible light but opaque to short radio waves.
  • Another example provided is the window of a microwave oven, which is transparent to microwaves but not to visible light.
  • Lead glass is mentioned in the context of radiation shielding, with uncertainty about its effectiveness against gamma radiation.

Areas of Agreement / Disagreement

Participants express varying views on the relationship between refractive index and density, with some acknowledging the complexity of optical properties across different materials and wavelengths. The discussion remains unresolved regarding the implications of these observations.

Contextual Notes

Participants highlight the need to differentiate between optical density and mass/volume density, indicating that assumptions about these properties may influence interpretations of experimental results. There is also an exploration of transparency and opacity across different wavelengths, which remains a nuanced topic.

Who May Find This Useful

This discussion may be of interest to students and educators in physics and optics, as well as those exploring the properties of materials in relation to light and electromagnetic waves.

resurgance2001
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Hi

Some of my students are doing an experiment, investigating the refractive index of different liquids such as water, alcohol, syrup (very concentrated sugar solution!), and oil.

The results that of their experiments seem to be showing that oil has a high refractive index than water and the sugar solution a lower refractive index. We thought at first that the refractive index would be linked to the density of the material. However, with these two liquids seems to be going in the opposite direction, as in, the liquid with the lower density actually has a higher refractive index.

Can anyone offer some alternative explanation(s) about how different materials affect the speed of light and hence refractive index.

Thanks

Peter
 
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Optical Density shouldn't be confused with mass/volume density of a substance.
Your case is a perfect example to explain the above!
 
Thanks - that is kind of what I was thinking - so we want to research optical density. Actually I was thinking how strange it is that different kinds of matter can appear transparent at some wavelengths such as radio and gamma but opaque at visible wavelengths. Are there any instances where light is transparent through at certain material at visible wavelengths but opaque to radio or other waves? I think not, except some materials that are visibly transparent do absorb infrared and UV - hmmm
 
The ionosphere is transparent for visible light but opaque for short radio waves.
 
resurgance2001 said:
Are there any instances where light is transparent through at certain material at visible wavelengths but opaque to radio or other waves?
The window of your microwave oven.

Lead glass gives radiation shielding, but I don't know whether that includes gamma radiation.
 
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