Im Messbecher sehe ich genau, wie viel Wasser wir für den Teig brauchen.

Im is a contraction of in dem.

• in = in
• dem = the, in the dative case

So im Messbecher literally means in the measuring cup.

It also tells you that the noun is der Messbecher in the dictionary form, because dem can be the dative form of a masculine noun.

Because German uses different cases after in depending on whether you mean location or movement.

• in + dative = being in a place
• in + accusative = going into a place

Here, the sentence is talking about a location: the speaker sees something in the measuring cup. There is no movement into the cup. So German uses dative:

• im Messbecher = in dem Messbecher

If it were about putting something into the cup, you might get in den Messbecher instead.

Because German main clauses follow the verb-second rule.

That means the finite verb must come in the second position of the clause. In this sentence, Im Messbecher comes first, so the verb sehe has to come next:

• Im Messbecher | sehe | ich ...

If you started with the subject instead, you would get:

• Ich sehe im Messbecher genau, wie viel Wasser wir für den Teig brauchen.

That is also correct. The version with Im Messbecher first gives a little more emphasis to the place.

Because that part is a subordinate clause.

More specifically, it is an indirect question: how much water we need for the dough.

German normally separates subordinate clauses from the main clause with a comma, so:

• Im Messbecher sehe ich genau, wie viel Wasser wir für den Teig brauchen.

The comma is required in standard German.

Because in a German subordinate clause, the conjugated verb usually goes to the end.

The subordinate clause here is:

• wie viel Wasser wir für den Teig brauchen

Inside that clause:

• wir = subject
• für den Teig = prepositional phrase
• brauchen = finite verb, placed at the end

This is very normal German word order for subordinate clauses.

Wie viel means how much.

It is used with something uncountable here:

• Wasser is an uncountable noun, so wie viel Wasser = how much water

If you were talking about countable plural things, you would often use wie viele, for example:

• wie viele Eier = how many eggs

As for spelling: in modern standard German, wie viel is usually written as two words. You may still see wieviel sometimes, but wie viel is the standard choice.

Den Teig is accusative because the preposition für always takes the accusative case.

• dictionary form: der Teig
• accusative: den Teig

So:

• für den Teig = for the dough

This is something worth memorizing: für is one of the prepositions that always require the accusative.

Yes, but it would mean something slightly different.

• im Messbecher focuses on what is visible in the measuring cup
• mit dem Messbecher means with the measuring cup or using the measuring cup

So:

• Im Messbecher sehe ich genau ... suggests that the cup itself, perhaps with its markings, lets you see the amount.
• Mit dem Messbecher sehe ich genau ... suggests the measuring cup is the tool you use to check the amount.

Both can make sense, but they are not identical.

Genau means exactly or precisely.

Here it emphasizes that the speaker can see precisely how much water is needed. It adds the idea of accuracy.

So the sentence is not just saying that the speaker sees the amount, but that they see it clearly and exactly.

Yes. German word order is flexible, especially in the main clause, as long as the finite verb stays in second position.

For example, these are both correct:

• Im Messbecher sehe ich genau, wie viel Wasser wir für den Teig brauchen.
• Ich sehe im Messbecher genau, wie viel Wasser wir für den Teig brauchen.

The difference is mainly emphasis:

• starting with Im Messbecher highlights the place
• starting with Ich is more neutral

The subordinate clause wie viel Wasser wir für den Teig brauchen is much less flexible, because its verb normally stays at the end.

That is the most natural neutral order in this subordinate clause.

German often places the subject relatively early in the clause:

• wie viel Wasser wir für den Teig brauchen

So the structure is:

• wie viel Wasser = the thing being asked about
• wir = subject
• für den Teig = prepositional phrase
• brauchen = verb at the end

Other orders are sometimes possible for emphasis, but this version sounds standard and natural.