Imagine yourself sitting in a noisy, crowded room. There are people sitting and standing everywhere, and each person seems to be carrying on a different conversation. You are also carrying on a conversation, when all of the sudden you here that your name was said. You turn around and you recall what that person was talking about seconds before they said your name, even though you were paying attention to the conversation that you were having. This is sensory memory in all of its glory.
Sensory memory in the true sense of the term a very short-term buffer memory where senses store what they have received before any cognitive processing within the brain occurs. It is a very short buffer; essentially lasting for 0.5 to 3 seconds. Imagine this type of memory as "scenic", being that it lasts for a short amount of time but has quite large capacity.
There are several types of sensory memory, essentially one for every sense as its name states. All of these types of sensory memory are essential to "get the whole picture" within ones memory. The sensory store is the window to short-term memory and long-term memory. So the next time you happen to hear your name in a crowded room, rub your hand on your head and say "thanks" to your sensory memory.