icicle
An icicle is ice in the shape of a cone or column that has formed from freezing drops . The lower end can be pointed or rounded, depending on the effect of the wind and the flow speed of the drops that form the icicle.
Emergence
At the beginning the icicle, which has not yet assumed its typical shape at this point, consists of a single drop . It grows as water runs down it drop by drop and freezes on the sides or at the top. Icicles occur in places where, on the one hand, liquid (melt) water accumulates (e.g. on the edge of a sunlit, snow-covered roof) and, on the other hand, temperatures below freezing prevail (e.g. below the edge of the roof, where the wind creates additional evaporative cold arises). The water has to freeze in layers so that the icicle can take on a mature shape.
A small, young icicle usually has a cone shape , and a few bubbles can often still be seen inside.
When an icicle grows, vertical ridges and horizontal ribs can form, the icicles grow both downwards (in length) and to the side (in width), but the growth takes place at a different rate (length growth is faster) .
Horizontal rings and vertical ridges
When an icicle is at a later stage of growth, the ribs are also more pronounced. However, the ribs become narrower and smaller towards the tip. The rings are separated from each other by a furrow. The ridges usually form after no water has congealed over the icicle for a long period of time. After such a phase, new meltwater begins to flow down the icicle in narrow paths, when this then freezes, thin ridges form that can be up to a centimeter thick.
top
The tip of a growing icicle consists of liquid water, which can hang several meters down. It is held together on the outside by a very thin skin made of ice crystals. A drop of water usually hangs at the very bottom of an icicle .
shape
The shape changes constantly; for example, a change in shape can take place through evaporation of ice. In general, icicles can be several meters long. After a certain length, however, the point is reached at which the pin can no longer be held due to its own weight and breaks off. Since falling icicles from roofs or similar can kill a person, it is important to remove icicles from paths and streets before they can become a danger.
Economic use
Prior to the widespread availability of means of refrigeration produced ice were to Eisgalgen large quantities generated at icicles, to then in ice cellars to be able to store and use for yearly cooling.
literature
- Johann Christoph Adelung: Excerpt from the grammatical-critical dictionary of the High German dialect . Volume 1, first part from A – E, Johann Gottlob Immanuel Breitkopf and Compagnie, Leipzig 1793.
- Mathias Asmus Claudius: Matthias Claudius works . Volumes 1–2, 1 volume, fourth edition, by Friedrich Perthes, Hamburg 1829, p. 64.
Web links
- H. Joachim Schlichting: Icicles that grow towards the sky. In: Spektrum.de , accessed on July 22, 2016
- Icicle. Planet School, accessed July 22, 2016
- Physicists explain waveform on the surface of icicles. From: Wissenschaft.de from November 20, 2002, accessed on September 12, 2019