To study the absorption of ultrasound in plexiglas we propose to use gadgets that are available to each student: an ultrasound humidifier, a liquid crystal display of a pad, a polaroid analyzer, a digital camera, a multimeter with thermocouple, and a stopwatch. These devices allow us to visualize a region in plexiglas where ultrasound is absorbed and to observe development of this region in dynamics because of the application of polarized light. With the help of these devices we can study the dependence of the temperature of plexiglas in the region of the ultrasound absorption on time and obtain quantitative estimates of the intensity of the ultrasound.