Fixing the shadows while moving the gnomon

TL;DR

This paper explores an innovative approach by moving the gnomon instead of fixing it to study shadows, enhancing understanding of latitude and shadow behavior through practical experiments during solstices.

Contribution

It introduces a novel method of analyzing shadows by moving the gnomon, providing new insights into the relationship between shadows, latitude, and solar position.

Findings

Demonstrated the method during solstices at two different sites.

Showed how moving the gnomon reveals shadow behavior related to latitude.

Validated the approach with practical experiments using simple tools.

Abstract

It is a common practice to fix a vertical gnomon and study the moving shadow cast by it. This shows our local solar time and gives us a hint regarding the season in which we perform the observation. The moving shadow can also tell us our latitude with high precision. In this paper we propose to exchange the roles and while keeping the shadows fixed on the ground we will move the gnomon. This lets us understand in a simple way the relevance of the tropical lines of latitude and the behavior of shadows in different locations. We then put these ideas into practice using sticks and threads during a solstice on two sites located on opposite sides of the Tropic of Capricorn.