A Colorful Demonstration of Thermal Refraction

TL;DR

This paper demonstrates heat flow refraction using a classroom experiment, supported by simulations, and connects the Tangent Law of heat refraction with fundamental principles like the Principle of Least Resistance and Least Time.

Contribution

It provides a novel classroom demonstration of heat refraction, derives the Tangent Law from fundamental principles, and offers modifiable simulations to explore heat flow behavior.

Findings

Results align with the Tangent Law of heat refraction

Simulations confirm the Principle of Least Resistance in heat flow

Demonstration illustrates unification of optics and thermodynamics

Abstract

The wave nature of heat flow mechanisms, such as lattice waves is discussed. Tan and Holland's Tangent Law of heat flow refraction is reviewed. A classroom demonstration of heat flow refraction through conductors in series is presented, and sample results are examined for consistency with the Tangent Law. To predict results, the Tangent Law is derived from the Principle of Least Resistance for this demonstration. User-modifiable simulations in Ruby and Ruby on Rails are presented, along with simulation results for various combinations of conductors. Results are interpreted in terms of the Principle of Least Time, illustrating a powerful unification in physics between disparate areas such as optics and thermodynamics.