curiosity

Children have an innate curiosity that drives them to ask 'why' about everything they see.

(Chinese) 孩子们天生具有好奇心，促使他们对所见的一切都追问“为什么”。

I opened the mysterious envelope out of pure curiosity, not expecting anything important.

(Chinese) 我纯粹出于好奇打开了那个神秘的信封，并没指望有什么重要的东西。