Physical noise is sights, sounds, and other stimuli in the environment that draw peoples attention away from its intended meaning. Physical noise can be a sound like the radio playing while your studying. It may also be a beautiful woman who walks into the restaurant that you work at and your distracted by her and don't hear the order for steak that your customer just gave to you. This is classified as physical noise.
Psychological noise is internal distractions such as thoughts, feelings, or emotional reaction to symbols and can fall into two categories: internal noise and semantic noise.
Internal noise is the thoughts and feelings that compete for attention and interfere with the communication process. This includes tuning out your professors lecture and tuning into a daydream or a past conversation.
Semantic noise refers to the distractions aroused by certain symbols that take our attention away from the main message. If a friend describes a 40-year-old secretary as "the girl in the office," and you think girl is a odd and condescending term for a forty year old woman, you might not even hear the rest of what your friend had to say.