This thesis deals on the one hand with the experimental evidence for thermal polarization fluctuations of a ferroelectric silver sodium dinitrite crystal and on the other hand with the experimental investigation of fluctuation theorems. In this context, the evidence of thermal polarization fluctuations of the solid crystalline ferroelectric material is achieved by measuring the resulting thermal noise current of the silver sodium dinitrite crystal in short-circuit. Based on this, the ferroelectric phase transition of silver sodium dinitrite is studied by this noise current measurement. For the experimental investigation of the fluctuation theorems, an electric, sine-driven parallel RC circuit is used. For this system will be checked, whether the thermal fluctuations of the injected energy and the total entropy production can be described by the fluctuation theorems for work and for total entropy production. Based on the measurements carried out, it can be determined that the resistance-capacity circuit used in this process is a very suitable alternative to the colloidal systems which are usually used for the experimental examination of fluctuation theorems.