Conservation of energy (or the lack thereof)

[Kristinn Leifsson]

Dear Brian,

The jar is not a closed system and therefore energy will be transferred
into the environment if the energy level of the jar is higher than that of
the surroundings.  This is vice versa if the immediate surroundings have a
higher energy level than the jar.  Remember, in this case when putting
metal into HCl, the potential energy of a squashed spring is transformed
into quite an amount of thermal energy which then readily escapes the jar.  

Maybe this analogy will reassure you and kill off your fear of opening the
jar: 
If you drop a can of coke and open it the DAY AFTER, you will live to tell
the tale.  


P.S. You should still wear goggles!


Kristinn Leifsson
Reykjavík, Iceland


>I confess that I haven't actually done this, but consider taking a handful
of jack springs and squashing them into a small jar containing hydrochloric
acid (let 'em know whose the boss).  Somehow screw on the lid without the
little beasties springing back out and splashing the acid over your hands.
Observe the springs being slowly dissolved away by the acid.  
>  
>Question (which I'm not entirely sure what the answer is):  Where does the
potential energy go that was contained in the squashed springs?  Newton
said that energy must go somewhere, but in this case - where?  

Brian Holden, BSc and piano tuner NZ.  
>