Das Kind macht mit der Seife Schaum in der Badewanne.

Because Kind is a neuter noun in German, so its nominative singular article is das.

• das Kind = the child
• plural: die Kinder = the children

German noun gender is grammatical, not always based on biological sex. So even if the child is a boy or a girl, the word Kind itself is still neuter.

In a normal German main clause, the finite verb usually comes in position 2.

Here the sentence is:

• Das Kind = subject
• macht = finite verb
• the rest = other sentence elements

So the pattern is:

• Das Kind macht ...

This is one of the most important German word-order rules. Even if you move another element to the front, the finite verb still stays in second position:

• In der Badewanne macht das Kind mit der Seife Schaum.
• Mit der Seife macht das Kind in der Badewanne Schaum.

Because mit always takes the dative case.

The noun Seife is feminine:

• nominative: die Seife
• dative: der Seife

So:

• mit der Seife = with the soap

This is a very common pattern in German:

• mit dem Kind
• mit der Seife
• mit den Kindern

Because German articles change depending on case, not just gender.

For a feminine noun:

• nominative: die
• accusative: die
• dative: der
• genitive: der

So Seife is still feminine, but after mit, it must be dative, so die Seife becomes der Seife.

Because in is a two-way preposition. It can take either:

• dative for location: where something is
• accusative for direction/movement toward: where something is going

Here, the child is making foam in the bathtub, meaning inside the bathtub / located there, so German uses dative:

• in der Badewanne = in the bathtub

Compare:

• Das Kind sitzt in der Badewanne. = The child is sitting in the bathtub.
• Das Kind steigt in die Badewanne. = The child gets into the bathtub.

Same reason as with der Seife: the preposition determines the case.

Badewanne is feminine:

• nominative: die Badewanne
• accusative: die Badewanne
• dative: der Badewanne

Since in here expresses location, it takes the dative:

• in der Badewanne

Because Schaum is being used as a mass noun here, in a general sense, much like foam in English.

So:

• Schaum machen = to make foam / create suds

German often leaves out the article with uncountable or material-like nouns when speaking generally. In this sentence, Schaum is not one specific, countable item.

You could sometimes see an article in other contexts, but here Schaum without an article is the natural choice.

Yes. Schaum machen is a natural expression meaning to produce foam, lather, or suds.

In this sentence, it means the child is using the soap to make bubbles or soapy foam in the bathtub.

Depending on context, German might also use more specific expressions, but Schaum machen is perfectly normal and easy to understand.

It tells you the means or instrument used to create the foam.

So the structure is roughly:

• Das Kind = who does it
• macht = does/makes
• mit der Seife = using the soap
• Schaum = what is produced
• in der Badewanne = where it happens

So mit der Seife functions a bit like with the soap or using the soap in English.

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

For example, these are also possible:

• In der Badewanne macht das Kind mit der Seife Schaum.
• Mit der Seife macht das Kind in der Badewanne Schaum.

These versions shift the emphasis a little, but the basic meaning stays the same.

The original sentence is neutral and straightforward.

Because in German, all nouns are capitalized, not just proper names.

So in this sentence:

• Kind
• Seife
• Schaum
• Badewanne

are all capitalized because they are nouns.

This is a standard spelling rule in German.

Schaum is in the accusative case, because it is the direct object of macht.

The child is making foam, so Schaum is the thing being made.

In this sentence, you do not see a special article marking the accusative, because there is no article in front of Schaum. But grammatically, it functions as the direct object.

Yes. It is the 3rd person singular form of machen:

• ich mache
• du machst
• er/sie/es macht

Since das Kind is singular, the verb is macht.

So:

• Das Kind macht ... = The child makes / is making ...

In context, English may translate this more naturally as is making rather than simply makes.