People can experience sounds as colours or tastes as touch sensations etc. The same sensory input may be perceived in different ways at different times. For the stimulation we receive through our sense organs is instantaneously organized and transformed into experiences that we refer to as perceptions. Sensation: the stimulus-detection process by which our sense organs respond to and translate environmental stimuli into nerve impulses that are sent to the brain. Perception: making sense of what our senses tell us the active process of organizing this stimulus input and giving it meaning its an active and creative process. Brain cant understand light waves, sound waves, or other forms of energy that make up the language of environment. Contact with the outer world is possible only because certain neurons have developed into specialized sensory receptors that can transform these energy forms into the code language of nerve impulses. Receptors deep within the brain monitor the chemical composition of our blood.