Sensory memory- .5 to 3 seconds
Short term memory- a minute or two, it can hold 5-9 bits of information- rehearsal will keep it in the short term, rehearsal for a long time or if it has great emotional value, it will go to long term
long ter memory- endless

Try this: Look at these letters for 30 seconds, then look away and solve this math problem: 3x +6= 12 x=?

ABC.NFL.NBA.CNN.USA.TBS

Now write down all the letters you remember. (Your short term only remembers 5-9 items, since these letters are familiar in the USA, you'll be able to remember more items if you give them meaning!)