Abstract This research aims to analyze the mechanism of the toppling dominoes. In order to measure accurately the changes of angles at which the dominoes rapidly fall and crash into another, we use an angle gauge converted from a precision adjustable resistor. In addition, we design a USB interface circuit along with a graphic user interface to receive signals from the angle gauge and then keep track of them in the computer. Based on the data collected, we can further analyze the mechanism, kinetic energy, and energy transfer of toppling dominoes. We find that the inelasticity of collision between dominoes leads to the loss of total kinetic energy, and thus the potential energy recruits the total kinetic energy