The simple setup was realized to analyze samples of water vapor collected from the solid surface adsorbent in the form of corundum ceramic balls. The adsorbent was previously saturated with water vapor from a source of distilled liquid water without dissolved gases. Testing of samples is carried out in a glass vessel isolated from the adsorbent by means of a forced change of pressure of vapor in the vessel. The necessary pressure rise occurs at the moment when steam is let into the vessel and the pressure drops during the vacuum pumping of water vapor. It was found that the samples respond differently to the rate of pressure change. This characteristic of gaseous mediums is associated with a significant quantity of discharged water molecules. It was found that the tested samples are clearly divided into two types according to the rate of pressure change. The first few samples behave in a similar way, but the behavior of the remaining samples is very different. It depends on the serial number of the sample. Samples demonstrate the self-similarity effect at the final stage of the experiment. In this case the rate of change of pressure smoothly decreases to a value of 3/4. This study found that the properties of water vapor can change during desorption from the adsorbent, in contrast to the current view that all desorbed water molecules are identical in their properties.