schmelzen
to melt
To change from a solid to a liquid state through heat.
Das Eis in der Sonne beginnt zu schmelzen.
The ice in the sun begins to melt.

to melt
Loading your saved state.
to melt
To change from a solid to a liquid state through heat.
Das Eis in der Sonne beginnt zu schmelzen.
The ice in the sun begins to melt.

The perfect tense of 'schmelzen' (to melt) is formed with 'sein' when something melts by itself (change of state). It is formed with 'haben' when someone actively melts something (action with an object).
Der Schneemann ist in der Sonne geschmolzen.
The snowman melted in the sun.
'Schmelzen' (to melt) can be used transitively (with an accusative object) or intransitively (without an object). When it is intransitive, the subject is the thing that is melting. When it is transitive, the subject actively melts the object.
Die Butter schmilzt in der heißen Pfanne.
The butter is melting in the hot pan.
In a figurative sense, 'schmelzen' (to melt) or 'dahinschmelzen' (to melt away) describes that something, usually something abstract like money, hope, or a lead, slowly becomes less and disappears.
Sein Vorsprung schmolz mit jeder Runde.
His lead melted away with every lap.
The expression 'dahinschmelzen' (to melt) is often used to express a very strong positive emotional reaction. You are extremely moved by or taken with something or someone.
Als er ihr das Kompliment machte, schmolz sie dahin.
When he gave her the compliment, she melted.
to solve / loosen
'lösen' and 'schmelzen' can easily be confused because in both cases a solid substance seems to disappear or become liquid. Use 'schmelzen' when heat turns a solid substance into a liquid, for example ice or chocolate. Use 'lösen' when a substance is distributed in a liquid, for example sugar in tea or salt in water. The simple difference is: something melts through heat, and something dissolves in a liquid.

In der Sonne schmilzt das Eis auf dem Teller.
In the sun, the ice on the plate melts.
Der Zucker löst sich im heißen Tee schnell auf.
The sugar dissolves quickly in the hot tea.