Why does light travel slower in water?

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    Light Travel Water
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Discussion Overview

The discussion centers on the phenomenon of light traveling slower in water compared to its speed in a vacuum. Participants explore various explanations, including classical electromagnetic theory and quantum interpretations, while questioning the nature of light and its interactions with materials.

Discussion Character

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

Main Points Raised

  • Some participants suggest that light slows down in water due to interactions with water molecules, involving absorption and re-emission processes.
  • Others reference Maxwell's equations, noting that they allow for plane wave solutions with phase velocities dependent on the medium's permittivity and permeability.
  • A few participants express confusion about the concept of a "new wave" mentioned in a video, questioning whether it is still considered light.
  • Some argue that not all electromagnetic waves are classified as light, emphasizing that "light" typically refers to a specific range of frequencies that are visible to humans.
  • There are discussions about the implications of light traveling at different speeds in different media, with references to the refractive index and special relativity.
  • Participants discuss the mathematical descriptions of light and electromagnetic fields, with some advocating for a wave perspective over a particle perspective.
  • Concerns are raised about the lack of explanation regarding the change in direction of light when entering a medium like glass, with some attributing this to boundary conditions in electromagnetic field theory.

Areas of Agreement / Disagreement

Participants express a range of views on the nature of light and its behavior in different media, with no clear consensus reached. Some agree on the applicability of Maxwell's equations, while others challenge interpretations and the implications of light's speed in various contexts.

Contextual Notes

Discussions involve various assumptions about the definitions of light, the role of quantum mechanics, and the interpretations of electromagnetic theory, which remain unresolved. Participants also highlight the complexity of reconciling classical and quantum perspectives on light.

Who May Find This Useful

This discussion may be of interest to those studying physics, particularly in the areas of optics, electromagnetism, and quantum mechanics, as well as individuals curious about the nature of light and its interactions with materials.

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