Learn Hardcore German: Ich mache das Licht im Wohnzimmer an. - I turn on the light in the living room.

The dictionary form is anmachen = to turn on (a device, light, etc.).
In a normal main clause in the present tense, the verb splits:
- machen goes to position 2
- an goes to the end of the clause

So:

Ich mache das Licht im Wohnzimmer an.
literally: I make the light in the living room on.

In the infinitive or at the end of a subordinate clause, it stays together:

Ich will das Licht im Wohnzimmer anmachen.
…, weil ich das Licht im Wohnzimmer anmache.

What is the literal meaning of Ich mache das Licht im Wohnzimmer an?

Literally it is:

Ich – I
mache … an – make … on (turn on)
das Licht – the light
im Wohnzimmer – in the living room

So word-for-word: “I make the light in the living room on.”
Natural English: “I turn on the light in the living room.”

Is anmachen the only way to say “to turn on the light” in German?

No, there are common alternatives:

das Licht anmachen – very common, everyday, neutral.
das Licht einschalten – a bit more technical/formal (to switch on).
das Licht anschalten – also used, similar to einschalten.

For everyday speech, anmachen and anmachen / ausmachen (on/off) are very typical:

Ich mache das Licht an. – I turn the light on.
Ich mache das Licht aus. – I turn the light off.

Does anmachen have any other meanings I should be aware of?

Yes. Besides to turn on (a device/light), anmachen can also mean:

to hit on somebody / to come on to somebody (flirt, sometimes a bit crude):
- Er macht sie an. – He’s hitting on her.
to annoy / to tell someone off (regional/colloquial in some areas):
- Der Chef hat mich total angemacht. – The boss really told me off.

In your sentence Ich mache das Licht im Wohnzimmer an, the meaning is clearly “turn on” a light, because the object is das Licht. Context usually makes it obvious.

Why is it das Licht and not die Licht or der Licht?

Because Licht is neuter in German, and the definite article for neuter nouns in the nominative and accusative singular is das.

Nominative: das Licht ist hell – the light is bright.
Accusative: Ich mache das Licht an – I turn the light on.

Article pattern (singular):

masculine: der (Nom.), den (Acc.)
feminine: die (Nom./Acc.)
neuter: das (Nom./Acc.)

So with Licht (neuter), you get das Licht as the direct object.

What case is das Licht in, and how do I know?

das Licht is in the accusative case as the direct object of the verb.

The subject (who performs the action): Ich – I
The direct object (what is being turned on): das Licht – the light

The verb anmachen is a transitive verb: you turn something on, so that “something” becomes the accusative object.

You can test with a pronoun:

Ich mache es an. – I turn it on.
Here es is the accusative pronoun, confirming the object role.

Why is it im Wohnzimmer and not in dem Wohnzimmer?

im is simply a contraction of in dem:

in (in) + dem (the – dative, neuter/masc. singular) → im

So:

Ich mache das Licht in dem Wohnzimmer an. (correct, just more formal/spelled out)
= Ich mache das Licht im Wohnzimmer an. (normal everyday form)

The preposition in can take dative (location) or accusative (movement into).
Here it describes a location (where is the light?), so it takes dative:

das Wohnzimmer (neuter)
dative singular: dem Wohnzimmer → im Wohnzimmer

Why is Wohnzimmer written as one word and capitalized?

In German:

All nouns are capitalized.
- So Wohnzimmer must start with a capital W.
German often uses compound nouns: several words are joined together into a single noun.
- wohnen (to live) + Zimmer (room) → Wohnzimmer (living room)

You do not write it as two words: Wohn Zimmer ❌.
The correct form is Wohnzimmer ✅.

Can I change the word order and say Ich mache im Wohnzimmer das Licht an?

Yes, that is grammatically correct and natural:

Ich mache im Wohnzimmer das Licht an.
Ich mache das Licht im Wohnzimmer an.

Both mean the same. The nuance is only in emphasis and rhythm:

Ich mache das Licht im Wohnzimmer an. – neutral; slightly emphasizes das Licht first.
Ich mache im Wohnzimmer das Licht an. – slightly emphasizes the place first (where you’re doing it).

German word order is quite flexible as long as:

The conjugated verb (mache) stays in position 2 in a main clause.
The separable prefix (an) stays at the end.

Why can’t I say Ich mache an das Licht im Wohnzimmer?

Because in separable verbs like anmachen, an is not a preposition here; it is a verb prefix that belongs to machen.

anmachen (separable verb): an
- machen = to turn on
The an cannot take its own object; it just completes the meaning of the verb.

So:

✅ Ich mache das Licht an.
❌ Ich mache an das Licht. (sounds wrong; it’s like “I make on the light.”)

When an acts as a preposition, it behaves differently:

Ich stelle die Lampe an das Fenster. – I put the lamp at the window.
Here an really is a preposition and das Fenster is its object.
In your sentence, though, an is part of the verb anmachen, not a preposition.

How would I say this in the past tense (Perfekt)?

For separable verbs in the Perfekt (present perfect), the prefix is folded into the past participle:

Infinitive: anmachen
Past participle: angemacht

So:

Ich habe das Licht im Wohnzimmer angemacht. – I turned on the light in the living room.

Word order:

auxiliary verb (habe) in position 2
past participle (angemacht) at the end (still one word).

How would this look in a subordinate clause starting with weil?

In a subordinate clause, the conjugated verb goes to the end, and a separable verb stays together:

Main clause:
- Ich mache das Licht im Wohnzimmer an.
Subordinate clause with weil (because):
- …, weil ich das Licht im Wohnzimmer anmache.

So in subordinate clauses:

anmache (together) is placed at the very end.

Can I drop the article and say Ich mache Licht im Wohnzimmer an?

You can say Ich mache Licht an, but it sounds a bit different:

Ich mache das Licht im Wohnzimmer an.
→ very specific: the (known) light in the living room.
Ich mache Licht an.
→ more general: I’ll put some light on / I’ll turn on a light (no specific lamp or room highlighted).

Ich mache Licht im Wohnzimmer an is grammatically possible but sounds unusual; normally you’d either say:

Ich mache das Licht im Wohnzimmer an. (most natural)
or, more vague:
Ich mache im Wohnzimmer Licht an. (I’ll put on light in the living room.)

Is mache here the same verb as machen in sentences like Ich mache meine Hausaufgaben?

Yes. The base verb is machen (to do/make).

Ich mache meine Hausaufgaben. – I do my homework.
Ich mache das Licht an. – I turn the light on.

In the second case, machen + the prefix an- → anmachen = to turn on.
The conjugation of machen itself is regular:

ich mache
du machst
er/sie/es macht
wir machen
ihr macht
sie/Sie machen

The separable prefix just moves around depending on the sentence type.