Newbie: export command doesn't operate when I execute it using a script?

[sylvain.vedrenne@free.fr]

Hello,

>From the command line, export works as I expect, but when I execute an export 
command by launching a script, it doesn't work as I expect.

Example:

% cat try_it
  export VARIABLE=ItWorksFineImHappy
% export VARIABLE=DoesntWorkImConfused
% echo $VARIABLE
  DoesntWorkImConfused       (so far, so good)
% chmod +x try_it
% ./try_it
% echo $VARIABLE
  DoesntWorkImConfused

Did I miss something fundamental? 
I couldn't find the answer until now... Please help.

Sylvain.