What are the similarities and differences between classical and operant conditioning?

Both of
these terms are used in behavioral psychology. Classical conditioning involves an
involuntary behavior and a response. This was made most famous in the case of
Pavlov's dog who came to associate the sound of a bell with food. When he heard the bell, he
salivatedthinking that food would be forthcoming. Another form of classical conditioning occurs
when people associate commercial breaks with eating junk food. Commercials by themselves do not
create hunger, but when people start associating commercials with a break to get food, they
begin crave food every time there is a commercial break.  

Operant conditioning involves tying a reward or consequence to a
behavior. For example, if a child talks during class, he/she misses recess time.
Ideally, if a student misses enough recess, he/she will associate having to miss recess with
talking in class, and he/she will disrupt class less. Also, a teacher could tie good behaviors
to treats. If a student does well, he/she will receive a treat. The student comes to associate
good behavior with treats and he/she will act better.