The effects of water phase changes on the |Z| level as the temperature changes when the growth medium is organic growth (cf. adjacent figure). |Z| levels are averaged over the frequency range 10kHz to 20kHz.
By comparison, the tap water level of |Z| is indicated by a dashed line and the ground level of the soil (T = +22°C) with a set of “stars”. When the temperature of the soil has fallen from -3 °C to -8 °C as described by the “diamond” character set, the |Z| level is not standardized and the water in the soil is both liquid and solid. When the temperature drops to T = -8.5°C, there is a strong increase in the |Z| levels, followed by a standardization, which is described by a set of “open squares”. The rise of response means that the water in the soil is now completely frozen, as indicated by the 90 times increase in the |Z| level when the water level marked by the dashed line is used as the reference level.