Pavlov knew that when dogs were fed they salivated. He wanted to train the dogs to salivate on command. So every time he fed his dogs he rang a bell. Eventually Pavlov was able to ring a bell and the dogs would salivate even without food. This is called classical conditioning.
In classical conditioning there is a stimulus and a response. When the bell rings (stimulus) the dogs salivate (response). We also talked about how students are classically conditioned to change classes every time the bell rings in school.
