Authors: Prof. Dr. Philipp Weihs, Prof. Dr. Josef Eitzinger, Ing. Wolfgang Laube
Basic concept of the building block
The following experiment, which should be conducted on a homogeneous surface, demonstrates the influence of latent evaporation energy on surface area temperature. Students should understand the influence of evaporation on the energy balance and ground temperature and be able to measure and quantify this.
Description of the building block
The measurements can be taken within a time frame of two hours. By measuring the temperature of a surface area with the help of a thermal camera, spatial differences in temperatures on a surface are made visible.
Thermal pictures can be taken on a homogeneous paved surface.
Heated water with a higher temperature than the surface area is poured over a specified point. At the beginning, the thermal camera sees this wet surface as a hot point. When the water evaporates the heat is slowly drawn away from the wet surface area, leading to a decrease in temperature. This temperature decrease slowly, becoming visible in the thermal camera images. At the end of the experiment, the wet area is cooler than the dry surrounding surface area.
Both indoor and outdoor trial areas are appropriate, including areas of the BOKU trial sites in Groß-Enzersdorf and the Türkenschanze.
The building block is divided into four steps:
Step 1: Directions to conducting the experiment
Step 2: Setting-up the experiment
Step 3: Conducting experiment
Step 4: Analysing and interpreting the data
The course materials include:
- Short instructions to the building block
- A video (
- A theoretical explanation of the observed phenomena
- Recommendations for implementing the building block in the course
- Bibliography and links