  In this work, we investigate the phenomenon of a chain of falling dominoes
("domino effect") by an acoustical measurement with a smartphone. Specifically,
we will present an approximate model valid for a considerable range of
realistic parameters of the domino effect; a new, easy and low-cost
experimental method using acoustical data captured by smartphones; and a
comparison of these experimental data to the simplified treatment and to other,
more comprehensive theories. The results of the experiments show good agreement
with other measurements and theory, both advanced ones from the literature, and
our own simplified treatment: qualitatively the approach to a constant
propagation velocity of the domino front after a small number of toppled
dominoes as predicted by theory; quantitatively the numerical value of the
asymptotic propagation velocity. The example can be seen as a demonstration of
the use of mobile devices as experimental tools for student projects about a
phenomenon of "everyday physics", and in the same time of interest for current
research (the domino effect as a paradigm of collective dynamics with
applications e.g. in neuronal signal transduction.
