balls

how do u tell the difference between soft golf balls and hard ones

The manufacturers generally state what the compression (softness rating) of the ball is.  The lower the number, the more the ball compresses and hence the softer the ball.  Hard balls are usually around the 90+ mark and often marketed as distance balls.  Softer balls are often marketed as as spin or control balls.  For a beginner, I recommend going for a distance (hard) ball.  These spin less off the club so fly straighter and reduce the dreaded slice. 

If you have a bag of mixed balls and you want to sort them, drop them on a hard surface.  A hard ball will give a 'thunk' sound and a soft ball will give a 'click' sound.  The hard ball will also be louder.  I used this to explain to my lad when he asked how could different balls 'feel' different.  I'm sure Tim Hawkins has carried out some sort of Nutty Professor style experiment on this. 

The problem with the manufacturers 'rating' is that is quite subjective and can be manipulated quite easily. It is therefore almost impossible to compare between ball manufacturers.  Chris is correct in what says about the drop test, simply listening to the clunk as they bounce is a good way of comparing relative hardness in a mixed bag, as you become more experienced you'll be able to feel this with your clubs.  And yes, I did do a small test comparing sound spikes - if you're losing the will to live this is the thread:

http://golfshake.com/forums/view/480/Measuring_golf_ball_hardness_nerd_alert.html

one is a bit sofer, one is a bit harder!