Alkali Metals react with water to produce that metal’s hydroxide and liberate Hydrogen Gas. Why ‘loud booms’ in the title? Well look at these pretty amazing videos below!
Both videos present below show how alkali metals react when mixed with water… And it’s explosive! The first video showcasts a group of young people throwing bags of sodium in the water of a pond. And the reaction is pretty unexpected (for me at least!)
Go @ 37 sec if you have no time!
Don’t worry for the fish, it’s no poison!
As we move down the Alkaline Metal group (Group 1) in the periodic table, reactions become more vigorous and sometimes Hydrogen ignites and explodes. Yeah the energy liberated becomes always bigger! This next video has some clips of explosion. Also Francium Bomb in water! Actually, really cool:
Crazy, no? It could be the cause of some mystery booms, no? But will not explain the mysterious rumblings that are normally associated to them!
 And Water Is Amazingly Loud!){kind=link}