Dr. Rob Salgado
Department of Physics, Lawrence University
Relativity on Rotated Graph Paper
Minkowski Spacetime diagrams have been difficult to interpret because line segments representing equal spacetime-intervals have unequal Euclidean lengths. However, it turns out that the areas of their respective "causal diamonds" are equal [in both Minkowskian and Euclidean geometries]. (The causal diamond of a timelike segment is the intersection of the causal-future of the past-endpoint with the causal-past of the future-endpoint. This appears as a parallelogram with lightlike edges, with the segment as a diagonal. Physically, this represents one tick of an inertial observer's light-clock.) Using rotated graph paper, we develop a physically-motivated geometrical method to do the standard calculations in special relativity---by counting boxes and using a minimal amount of algebra. This has been used to teach relativity to introductory physics students. (A draft of my article is available at: http://arxiv.org/abs/1111.7254. It is undergoing substantial reorganization.) We conclude with my current efforts to extend this method to uniformly-accelerated observers. [Graph paper and colored pens will be provided.]
Wednesday 22 May
Youngchild 115
4:00pm
