  Please find the final and published version of the manuscript using this
citation: E. Bernhardt, et. al, "An apparatus for measuring a material's
photomechanical response", American Journal of Physics, 86, 14 (2018)
  This paper describes a simple and inexpensive apparatus for measuring the
light-induced shape change of a material, which can be implemented in a high
school or undergraduate laboratory. The key components are a laser pointer to
actuate the material, a force sensor from an inexpensive jeweler's balance to
measure the response, an Arduino for data acquisition and a means for
mechanically mounting the components. The apparatus described here was used by
high school students and teachers in a summer program to characterize liquid
crystal elastomers. The theory of the photomechanical response is used to
interpret the data, from which the material parameters are determined.
