A simple explanation of sense perception might go as follows: perception is conscious reception of perceptual qualities of an external object. When I see a duck or hear a chime of a bell, the color and shape of the duck – or the vibration of air that the bell causes – act upon my senses, and I become aware of these qualities. However, sense perception is rarely such a simple process, since we do not perceive isolated qualities. Sounds that we hear and colors that we see are moving or at rest, and they have certain intensity or size and a location in relation to us and to other objects. Moreover, our perceptions require that we pay attention to our surroundings, and often we make various kinds of judgments and react emotionally to things that we perceive, and so forth.