The picture shows the phase transition of water. The description is in German.
<a href="//commons.wikimedia.org/wiki/User:Minihaa" title="User:Minihaa">Minihaa</a>
2018-01-07
Own work based on: <a href="//commons.wikimedia.org/wiki/File:Aggregate_phase.svg" title="File:Aggregate phase.svg">Aggregate phase.svg</a> <i>by</i> <a href="//commons.wikimedia.org/w/index.php?title=User:Synkizz&amp;action=edit&amp;redlink=1" class="new" title="User:Synkizz (page does not exist)">Synkizz</a>  and <a href="//commons.wikimedia.org/wiki/File:Aggregatzustands%C3%A4nderung_von_Wasser_Deutsch.svg" title="File:Aggregatzustandsänderung von Wasser Deutsch.svg">Aggregatzustandsänderung von Wasser Deutsch.svg</a> <i>by</i> <a href="//commons.wikimedia.org/w/index.php?title=User:Synkizz&amp;action=edit&amp;redlink=1" class="new" title="User:Synkizz (page does not exist)">Synkizz</a>