Can you find the missing piece of the Porsche?

John enters a small room. The Door Closes.
When the door opens, John is in a larger room.

Explain?

I am white when I am dirty, and black when I am clean. What am I?

Known by all without exception, Forever here, for your protection, Sometimes strong, sometimes weak, Right after the night I come - hot and chic. And while millions of miles away, I always get to you, I find my way. No life around could do without me, Can you guess what I might be?

What is the Surname of Barbie Doll?

It comprises roots which nobody sees,
Much taller than those trees,
Up and up it goes,
Still it never grows?

One day, John and his friends were playing around. Jacob hit something with a Pin and it popped. John's dad came into the room that very moment, but he wasn't mad. In fact, he was smiling. What did Jacob hit?

What is the riddle which can be asked all day with a different correct answer each time.

I came first on earth but second on the heaven.
I also came twice in a week but found just once in a year.
I stay away from months but you can find me in February.

What am I?

I am weightless, but you can see me. Put me in a bucket, and I'll make it lighter. What am I?