Hi, all. Would anyone suggest your own idea about what actually spin it is? I can not form an image in my head about spin... Spin is vector, can be 1/2 can be 1, and if say it is 1/2, then Spin's Z component can be -1/2 or +1/2 ...??!! and the magnitude of spin vector is: |S| = sqrt(S(S+1)) ???!! how to really really understand it? Please leave your own idea, it will be great helps! Thanks in advance!