Heron's fountain
A Heronsbrunnen is a fountain named after its inventor Heron of Alexandria , which seems to work endlessly without any outside influence. In truth, water is pumped from a reservoir into a higher basin, so that the fountain is kept running by the interaction of the air pressure and the connected containers until the output reservoir is empty. Depending on the size, such a Heronsbrunnen can function for hours without external work or energy having to be added. However, it is not a perpetual motion machine .
The illustration shows the principle of the Heronsbrunnen . The water that is collected in the uppermost container, which is open at the top, flows into the lower container K1 and compresses the air it contains above the water level through the pressure of the water column at height D. This air pressure is sent through another pipe to the middle container K2 passed on, which in turn acts on the water level there and pushes the water out through the central tube leading upwards with a final nozzle , so that a fountain is created. The water from the fountain is caught in the upper container, so that a closed circuit is simulated.
At the beginning, container K1 is empty and container K2 is full. The water level in container K1 rises over time by the same volume as it falls in container K2. The well dries up as soon as tank K2 is empty. Apart from losses due to evaporation or splashing, all of the water is then in the container K1.
The potential energy of the water in the uppermost collecting container is converted into kinetic energy in the fountain. If friction losses are neglected , the fountain height is determined by the ever decreasing pressure difference D, so that the height of the fountain also decreases over time.
The necessary potential energy is initially given to the well by the fact that the water has to be transported from the container K1 into the container K2, whereby mechanical work has to be performed.
Example of a Herons fountain made of Plexiglas
literature
- Johann Heinrich Jacob Müller: Textbook of Physics and Meteorology. Volume 1, printed and published by Friedrich Vieweg and Son, Braunschweig 1843.
- Otto Lehmann: Physical technique: or instructions for experimental lectures . First volume, second section, published by Friedrich Vieweg and Son, Braunschweig 1905.
- Wilhelm H. Westphal (Ed.): Physical dictionary. Two parts in one volume, Springer Verlag Berlin Heidelberg, Berlin Heidelberg 1952.
See also
Web links
- Heronsbrunnen (accessed January 7, 2016)
- Experiments at Bielefeld University on the subject of air. (accessed on January 7, 2016)