Seeing Merging Shadows in the Sunlight

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Discussion Overview

The discussion revolves around the phenomenon of merging shadows observed in sunlight, specifically in the context of a hand and a container. Participants explore possible explanations for this occurrence, including the influence of light angles and shadow effects.

Discussion Character

  • Exploratory
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • One participant notes that the merging of shadows may relate to the angle of the light source, similar to how shadows are cast by a gnomon in a sundial, which varies with time of day.
  • Another participant suggests the phenomenon could be attributed to the shadow blister effect.
  • A later reply expresses skepticism about the initial explanation regarding the sundial, indicating a belief that it does not fully capture the observed effect.
  • Some participants mention the idea of shadows appearing to attract each other at certain distances, raising questions about the nature of shadow interactions.

Areas of Agreement / Disagreement

Participants do not reach consensus on the explanation for the merging shadows, with multiple competing views presented, including the sundial analogy and the shadow blister effect.

Contextual Notes

Participants express uncertainty regarding the definitions and implications of the shadow blister effect and the relationship between shadow merging and light angles. There are indications of missing assumptions in the explanations provided.

Who May Find This Useful

This discussion may be of interest to individuals exploring optical phenomena, shadow behavior, and the effects of light sources on shadow formation.

Vibhu
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Today when I was standing beside a container in sunlight I observed that the shadow of my hand merged at a certain distance with of the container even though their was enough distance between my hand and container for light to pass is there a reason?
 
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Yes, there's a reason. If you consider a sundial, you'll recognize that the shadow cast by the gnomon depends on the angle of the gnomon relative to the light source, i.e. the sun, which depends on the time of day.

16b1c27e92c406007b2d9ca80b77eb5d.gif


If a small bird were to alight on the III in the illustration, none of its shadow would be merged with that of the gnomon, but if it were to alight on the IX, almost all of its shadow would be merged with that of the gnomon, and the distance from the gnomon of the III and the IX is about the same.
 
sysprog said:
Yes, there's a reason. If you consider a sundial, you'll recognize that the shadow cast by the gnomon depends on the angle of the gnomon relative to the light source, i.e. the sun, which depends on the time of day.

View attachment 241378

If a small bird were to alight on the III in the illustration, none of its shadow would be merged with that of the gnomon, but if it were to alight on the IX, almost all of its shadow would be merged with that of the gnomon, and the distance from the gnomon of the III and the IX is about the same.
It looked like the Shadows were attracting each other after a certain distance each time I did it. Thank you for this explanation but I don't think it is correctly defining it.
 
DrClaude said:
Or it may be the shadow blister effect.
Also not this one, I read this one and was very knowledgeable.
 
Vibhu said:
It looked like the Shadows were attracting each other after a certain distance each time I did it. Thank you for this explanation but I don't think it is correctly defining it.
That seems more like the shadow blister effect phenomenon to which @DrClaude alluded, but given that you disclaim that, perhaps you could provide a more detailed description.
 
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