Psyche 16 - Golden asteroid, why it is easy to swim on sea as compared to river ?,why clouds happen black at a time of rainfall?, How many colours we can see through our eyes?,Gallium melting point?, how to block out sleep in night?, world's most expensive thing,gold minesbr br Baarish ke samay baadal kaale kyon ho jaate hain?,br br Samudra me tairna zyada aasan kyon hota hai?,br br Raat me zyada kaise jaage ?,br br Duniya ki sabse mahegi cheez,br br Sone ki minesbr br