Good Riddles

Question: 5 bricks construct me, you'll find a candle in the middle. I am the antithesis of heavy, Without me you couldn't read the riddle. What am I?

Question: An electric train is traveling south. Which way does the smoke go?

Question: A father's child. A mother's child. no one's son.

Who am I?

Question: You can rest on my pad without touching the keys.
I will sing all month long as long as you pay your fees.

What am I?

Question: When you close it, you see mysterious and funny looking images. But if you open it, the mysterious images are gone. What Am I?