It is easy for us to feel emotions but it is quite complicated to study them. According to many researches in this field, emotions have components of two types: physical and mental and consist of body responses, expressive behavior and subjective feelings. We feel emotions by our brain and it is really difficult for scientists to give a single accurate definition for this process. However, experts say that emotions are our mental state along with facial expressions, actions or physical changes. They are related to our mood, but differ from it, as they are short lived feelings with a clear object and mood is a more general feeling and lasts longer. For example, one can be happy about something or angry with somebody this is his emotion. But another one can have a general feeling of pleasure, anxiety or sadness this is his mood.