Plastik werfen wir in den Gelben Sack, damit es recycelt werden kann.

We throw plastic into the yellow bag so that it can be recycled.

Breakdown of Plastik werfen wir in den Gelben Sack, damit es recycelt werden kann.

• wir: we
• es: it
• in: into
• können: can
• damit: so that
• den: the; (masculine, accusative)
• das Plastik: the plastic
• gelb: yellow
• werfen: to throw
• der Sack: the bag
• recycelt werden: to be recycled

Questions & Answers about Plastik werfen wir in den Gelben Sack, damit es recycelt werden kann.

Why does the sentence start with Plastik instead of Wir?

German often puts what you’re talking about first (the topic) for emphasis or contrast. By starting with Plastik, the speaker highlights plastic specifically (as opposed to glass, paper, etc.).
Because something other than the subject is in position 1, the finite verb still stays in position 2, so you get Plastik werfen wir ... (not Plastik wir werfen ...).

Why is it werfen wir and not wir werfen?

This is standard verb-second (V2) word order in main clauses. If Plastik is in the first position, the verb must come next, and the subject follows:
Plastik (1) + werfen (2) + wir (3) + ...

What case is Plastik here, and why?

Plastik is the direct object, so it’s in the accusative. Many nouns look the same in nominative and accusative, so you mainly notice the case through articles (e.g., den later in the sentence).

Why is it in den Gelben Sack (accusative) and not in dem Gelben Sack (dative)?

With the “two-way” preposition in, German uses:

• accusative for movement/direction (into something): in den Sack
• dative for location (in = inside/within, no movement): in dem Sack

Here the idea is “throw it into the bag,” so accusative is used: in den Gelben Sack.

Why are Gelben and Sack capitalized, and why is Gelben ending in -en?

• Sack is a noun, and all German nouns are capitalized.
• Gelben is part of the noun phrase der Gelbe Sack (a specific thing), so it’s also capitalized here because it’s functioning like a named system/category (and is commonly treated like a fixed term).
• The adjective ending -en comes from accusative masculine after den: in den gelb-en Sack.

Is Gelber Sack something cultural/specific, or just “a yellow bag”?

It’s often a specific German recycling term. Der Gelbe Sack refers to the yellow bag used in many parts of Germany for certain packaging waste (often plastics/metal packaging). In everyday German, people commonly use it as a set phrase.

What does damit do here, and why is the word order different after it?

damit introduces a purpose clause meaning so that / in order that. It’s a subordinating conjunction, so it sends the conjugated verb to the end of the clause:
..., damit es recycelt werden kann.
Here the finite verb is kann, so it appears at the very end.

What does es refer to?

es refers back to Plastik. German often uses es to refer to a previously mentioned thing, especially when it’s treated as an uncountable/material noun like Plastik.

Why does it say recycelt werden kann (two verbs at the end)?

This is a combination of:

• werden to form the passive: recycelt werden = to be recycled
• können as a modal verb: ... werden kann = can be ...

In subordinate clauses, German stacks verbs at the end. The order here is typical: participle + infinitive + finite modal
recycelt (participle) + werden (infinitive) + kann (finite).

Could I also say ..., damit man es recyceln kann? Is there a difference?

Yes. Both are common, but they feel slightly different:

• damit es recycelt werden kann = emphasizes the process/result (passive: “so that it can be recycled”)
• damit man es recyceln kann = emphasizes that people/the system can recycle it (active with man)

They’re often interchangeable in everyday meaning.

Is werfen the most natural verb here? What are alternatives?

werfen is correct and understandable, but in everyday “sorting trash” context, Germans also often use:

• (etw.) in den Gelben Sack werfen (fine, a bit vivid)
• (etw.) in den Gelben Sack tun (very common, neutral)
• (etw.) in den Gelben Sack werfen/entsorgen (more formal with entsorgen = dispose of properly)

So your sentence sounds natural; tun might sound a bit more casual/typical.

Why is it werden kann and not kann werden?

Because this is a subordinate clause introduced by damit, and German places the finite verb at the end. The finite verb here is kann, so it must be last:
..., damit es recycelt werden kann.
In a main clause, you’d get: Es kann recycelt werden.