Learn Hardcore German: Unsere ehrgeizige Erzieherin bleibt auch dann gelassen, wenn die Kinder im Kindergarten durcheinander rufen. - Our ambitious preschool teacher stays relaxed even when the children in kindergarten shout all over the place.

Erzieherin is grammatically feminine (the -in ending marks the female form).
In this sentence, she is the subject, so the noun phrase is in the nominative case.
Feminine nominative with a possessive determiner unser- takes the ending -e:
- unsere Erzieherin (our female educator)
- ehrgeizige Erzieherin (ambitious female educator)

So both unsere and ehrgeizige get the -e ending: Unsere ehrgeizige Erzieherin.

If it were masculine, it would be: Unser ehrgeiziger Erzieher (no -e on unser, -er on ehrgeiziger).

What exactly is an Erzieherin? How is it different from Lehrerin?

Erzieherin: an educator, usually someone working in early childhood education (kindergarten, daycare, after‑school care). Focus is on childcare, development, and social skills.
Lehrerin: a (female) school teacher, usually in primary or secondary school, focused on teaching school subjects.

In the sentence, Erzieherin fits well because it talks about Kinder im Kindergarten (children in kindergarten).

Why does the sentence use bleibt … gelassen? Can you explain this structure?

Bleiben + adjective describes a state that continues:

bleibt gelassen = “stays/remains calm”

Structure:

bleiben is the conjugated verb (3rd person singular: bleibt),
gelassen is an adjective here meaning calm, composed, unruffled.

So Unsere ehrgeizige Erzieherin bleibt … gelassen = “Our ambitious educator stays calm …”

Is gelassen here an adjective or a past participle? What’s the nuance?

Formally, gelassen is the past participle of lassen, but in this structure it behaves like an adjective meaning calm / composed.

Compare:

Er ist sehr gelassen. – He is very calm. (clearly adjective)
Er bleibt gelassen. – He stays calm.

So you don’t need to think of lassen actively here; just treat gelassen as an adjective = “calm and unbothered.” It’s a bit more “stoic” and composed than simply ruhig.

What does auch dann … wenn express? Could you just say wenn?

wenn alone = “when/whenever/if”:
Sie bleibt gelassen, wenn die Kinder … rufen.
auch dann, wenn adds emphasis similar to “even when / even then when”:
Sie bleibt auch dann gelassen, wenn …
→ “She stays calm even when …”

You could drop auch dann grammatically, but you’d lose the nuance that her calmness is impressive despite the chaos.

Why does the verb go to the end in wenn die Kinder im Kindergarten durcheinander rufen?

Because wenn introduces a subordinate clause, and in German subordinate clauses the conjugated verb goes to the final position.

Structure:

wenn (subordinating conjunction)
die Kinder im Kindergarten durcheinander (subject + adverbials)
rufen (verb at the end)

So:
…, wenn die Kinder im Kindergarten durcheinander rufen.
This verb‑final word order is required after wenn (and after other subordinating conjunctions like weil, dass, obwohl, als, etc.).

What’s the function of the comma before wenn?

German grammar requires a comma between a main clause and a subordinate clause.

Main clause: Unsere ehrgeizige Erzieherin bleibt auch dann gelassen
Subordinate clause: wenn die Kinder im Kindergarten durcheinander rufen

So you must write:
Unsere ehrgeizige Erzieherin bleibt auch dann gelassen, wenn die Kinder im Kindergarten durcheinander rufen.

What is im Kindergarten exactly? Why is it im, and what case is used?

im is a contraction of in dem:

in (preposition) + dem (dative neuter article for Kindergarten) → im

Kindergarten is masculine: der Kindergarten.
In the dative singular: dem Kindergarten.

The preposition in can take dative (location) or accusative (direction).
Here it’s a location: in the kindergarten, so it uses dative:

in dem Kindergarten → im Kindergarten.

What does durcheinander rufen mean, and why isn’t it one word like durcheinanderrufen?

durcheinander is an adverb meaning roughly “in confusion / all mixed up / over one another”.
rufen = “to call / shout”.

Together, durcheinander rufen means “to shout over one another / to call out in a chaotic way”.

You will often see it written as durcheinander rufen (two words: adverb + verb). In some contexts you might see durcheinanderrufen treated like a separable verb, but the “safe” and common analysis is:

durcheinander = adverb
rufen = main verb

In the sentence, durcheinander stands before rufen, but in a main clause with simple present it could be:

Die Kinder rufen durcheinander.

Why does die Kinder also look like nominative plural? Isn’t there any case change in the subordinate clause?

Yes, die Kinder is nominative plural and it’s the subject of the subordinate clause:

Main clause subject: Unsere ehrgeizige Erzieherin (nom. singular)
Subordinate clause subject: die Kinder (nom. plural)

German uses nominative for the subject in both clauses, independently.
die is both nominative and accusative plural, but here it’s nominative because die Kinder perform the action (rufen).

Could you say wenn die Kinder im Kindergarten durcheinanderrufen as one written word?

You do see durcheinanderrufen written as one word, treating durcheinander like a separable prefix. Many dictionaries accept both analyses.

However:

Written as durcheinander rufen, it’s clearly adverb + verb, and is very common and transparent.
Native usage varies, and both spellings can appear. In everyday writing, durcheinander rufen (two words) is perfectly natural and unproblematic.

For learning purposes, it’s easier to treat durcheinander as an adverb modifying rufen.

What’s the difference between gelassen, ruhig, and entspannt in this context?

All can relate to “calm,” but with different flavors:

ruhig – calm, quiet; opposite of noisy/agitated.
Focus more on external behavior or noise level.
entspannt – relaxed; opposite of tense/stressed.
More about inner state and tension.
gelassen – composed, unflappable, takes things in stride.
Suggests inner composure even under pressure.

Here gelassen hints that the educator stays mentally composed and unperturbed, even though there is chaos around her.

Why is present tense used here? Could it also describe a habitual action?

Yes. German Präsens (present tense) can express both:

A situation happening now.
A general or habitual behavior.

In this sentence it most naturally means:

“Our ambitious educator usually/always stays calm when the children shout chaotically in kindergarten.”

So it describes a typical behavior, not just a single event.