[The Seventh Blog] Fluids.

     Well it's been a while since we've done a blog and I honestly forgot about it till not too long ago, but that's okay because I still have ample time to finish it.  And luckily I found something to write about while scavenging through old trip photos, otherwise who knows what I'd be doing right now (maybe shooting my brother with a water gun or something...).  So anyway, here is the lovely picture that I came across of a pirate-y looking boat (in Japan, which just makes it all the better. :]).  

     
     Why is it that an object that seems so heavy can float on water?  I can understand rubber duckies floating in a bathtub, but gigantic ships floating on the ocean? I think not. But it's possible (anything is possible if you just believe. ^_^) and the explanation lies in PHYSICS, of course!  Contrary to what seems logical, it is really not the weight of an object that determines whether it will sink or float; it is the object's density as compared to the fluid's density that matters.  If an object's density is less than the fluid's density, it will float, and if it is greater than the fluid's density, the object sinks.  This must mean that the ship's average density is lower than the density of sea water. 
     Also, all objects placed in liquids have this thing called buoyant force acting on them.  This force counteracts the object's weight, pushing up on it from below.  Buoyant force is equal to ρVg (density of the liquid x volume submerged x gravity), also stated as the density of the liquid multiplied by the weight of the fluid displaced.  When buoyant force is greater than or equal to an object's weight, the object floats, and when it is less than the object's weight, the poor object sinks to the bottom.  And good thing there is physics to explain why the boat floats instead of sinking to the bottom of the ocean as would be expected if we didn't know any better, because I don't think the people on it would appreciate if it sank - who knows what creepy things are hidden far far below the ocean's surface...