Stearinljusen fick barnen att bli lugna medan vi väntade på att strömmen skulle komma tillbaka.

In this sentence, få is used in the pattern få + someone + att + infinitive, which often means to make/get someone to do something.

So:

• Stearinljusen fick barnen att bli lugna
• literally: The candles got the children to become calm
• natural English: The candles made the children calm down

This is a very common Swedish structure:

• Hon fick mig att skratta = She made me laugh
• Det fick honom att tänka efter = That made him think

So fick here is not received. It is the past tense of få in a causative sense.

Because bli means become, while vara means be.

• bli lugna = become calm
• vara lugna = be calm

The sentence describes a change of state: the children were not calm before, and then the candles caused them to become calm.

Compare:

• Barnen blev lugna = The children became calm
• Barnen var lugna = The children were calm

So bli is the natural choice here.

Because lugna agrees with barnen, which is plural.

After verbs like vara, bli, verka, and similar verbs, adjectives are often predicate adjectives, and they still agree in number and gender.

Here:

• barnet = the child → lugnt
• barnen = the children → lugna

Examples:

• Barnet blev lugnt = The child became calm
• Barnen blev lugna = The children became calm

So lugna is plural agreement.

They do two different jobs.

1. att bli lugna
   Here att is the infinitive marker, like English to in to become calm.

2. på att strömmen skulle komma tillbaka
   Here att introduces a clause after vänta på. It is closer to that in structure, even though English often does not translate it directly.

So:

• fick barnen att bli lugna = made the children become calm
• väntade på att strömmen skulle komma tillbaka = waited for the power to come back

Same word, different grammatical function.

The verb is vänta på = wait for.

When what you are waiting for is a whole action or event, Swedish often uses:

• vänta på att + clause

So:

• vi väntade på att strömmen skulle komma tillbaka
• literally: we waited for that the power would come back
• natural English: we waited for the power to come back

More examples:

• Jag väntar på att bussen ska komma = I’m waiting for the bus to come
• Hon väntade på att han skulle ringa = She waited for him to call

This is a very normal pattern in Swedish.

Because the return of the electricity was future from the point of view of the past.

The main verb is in the past:

• vi väntade = we were waiting / we waited

At that time, the electricity had not yet returned. It was something expected to happen later. Swedish often uses skulle + infinitive for that idea.

So:

• strömmen skulle komma tillbaka = the power would come back

Compare:

• Jag vet att han kommer = I know that he is coming / will come
• Jag visste att han skulle komma = I knew that he would come

That is exactly the same kind of shift here.

Because in this context Swedish usually uses the definite form when talking about the electricity / the power supply in a specific situation.

• ström can mean current, electricity, or power
• strömmen = the power / the electricity

In a power outage situation, Swedish naturally says things like:

• Strömmen gick = The power went out
• Strömmen kom tillbaka = The power came back

So the definite form sounds idiomatic here.

Here medan means while.

It emphasizes that two things were happening during the same period:

• the candles calmed the children
• we were waiting for the power to return

So:

• medan vi väntade = while we were waiting

Difference from när:

• medan = while, focusing on overlap in time
• när = when, often just locating an event in time

Examples:

• Jag läste medan hon lagade mat = I read while she cooked
• Jag läste när hon kom hem = I was reading when she came home

In your sentence, medan is the natural choice because the waiting was an ongoing background action.

Stearinljusen is the definite plural form of stearinljus.

The forms are:

• ett stearinljus = a stearin candle
• stearinljus = stearin candles
• stearinljuset = the stearin candle
• stearinljusen = the stearin candles

So Stearinljusen means the candles.

A native English speaker may notice that singular and plural indefinite look the same here:

• ett ljus
• två ljus

That is normal for many Swedish neuter nouns.

Yes, it is a very common verb phrase meaning come back or return.

• komma = come
• tillbaka = back

Together:

• komma tillbaka = come back

In this sentence it refers to the power returning:

• strömmen skulle komma tillbaka = the power would come back

You can use it for people, things, and situations:

• Han kommer tillbaka i morgon = He’s coming back tomorrow
• Min aptit kom tillbaka = My appetite came back

So it is a normal and useful everyday expression.

Because this is a subordinate clause after att.

In Swedish subordinate clauses, the subject normally comes before the finite verb:

• att strömmen skulle komma tillbaka

Structure:

• att
  • subject
    • finite verb
      • rest

So here:

• att
• strömmen = subject
• skulle = finite verb
• komma tillbaka = infinitive phrase

This is standard subordinate-clause word order.

A useful thing to remember is that subordinate clauses do not use the main-clause V2 pattern.

Yes, but the meaning changes slightly.

• Barnen blev lugna = The children became calm
• Stearinljusen fick barnen att bli lugna = The candles made the children become calm

The second version explicitly shows cause. It tells you what produced the calming effect.

So the original sentence is more informative because it connects the candles to the children’s reaction.