Grammar › N3 · 04 Reasons and causes
もの: thing; because (explanation)
N3 · 04 Reasons and causes
Means a tangible thing; sentence-final もの/もん gives a childish reason.
Noun もの = object (物) or person (者). 〜ものだ = natural tendency, nostalgia. Casual 〜もの/もん = "because", soft.
Examples
食べるものがありません。
There's nothing to eat.
だって、知らなかったんだもの。
Well, I just didn't know!