Sun shade on Earth ground, is it a straight line or a curved line?

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Discussion Overview

The discussion centers around the nature of the shadow cast by a pole or building on the ground due to sunlight, specifically whether the shadow forms a straight line or a curve. Participants explore the implications of this phenomenon in relation to latitude and time of year.

Discussion Character

  • Exploratory
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • One participant questions whether the shade from a pole or building is a straight line or a curved line, and how to calculate any curvature.
  • Another participant suggests that the situation likely depends on the observer's latitude and the time of year.
  • A third participant notes that the pole acts as a sundial, implying that the shadow's behavior is related to the angle of sunlight, which varies with latitude.
  • A later reply acknowledges the sundial analogy and emphasizes that the angle of the shadow will depend on the specific latitude of the observer.

Areas of Agreement / Disagreement

Participants express uncertainty about whether the shadow is straight or curved, with multiple viewpoints on how latitude and time of year may influence the shadow's characteristics. The discussion remains unresolved.

Contextual Notes

Participants have not specified the mathematical framework for calculating the curvature of the shadow, nor have they detailed the assumptions regarding the position of the sun or the geometry involved.

applied-physics
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Hi, I wonder if the shade from the sun on the ground, on a sunny day, is it a straight line or a curved line?? and if it is curved, how curvature can be calculated ?? Let´s say I have a pole or building, and I can follow up the shade of its top on the ground. I can make marks every 5 minutes or so. . Would that make a straight line, or a curve line ?? Thanks !

[Hi , I am an Electrical Engineer who has been teaching High School Physics for a while here in Santiago of Chile. I started with the Cambridge-IGCSE curriculum, and then I moved to the local curriculum. My interests are waves, ultrasound, near-infrared, electrical power systems, relies, universe and comets! Following Pons Brooks (perihelium April 21st 2024, nice shot here from Southern Hemisphere!), Tsuchinshan, ... others ! ]
 

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Welcome to PF. :smile:

applied-physics said:
Hi, I wonder if the shade from the sun on the ground, on a sunny day, is it a straight line or a curved line?? and if it is curved, how curvature can be calculated ?? Let´s say I have a pole or building, and I can follow up the shade of its top on the ground. I can make marks every 5 minutes or so. . Would that make a straight line, or a curve line ??
What are your thoughts so far? Do you have any ideas how you could sketch the situation to try to figure this out? It likely depends on your latitude and the day of the year, right?
 
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Your pole is an enormous sundial, is it not?
 
ooops, .. that is right ... that used to be a science fair project ... indeed a pole can be a sundial, right. I could make a clock. And the angle then will depend upon latitude. 33 south is mine here in Santiago. Many many thanks.
 
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