Another Classroom Conversation

Overheard in Miss Munchkin's classroom:

Teacher: Let's see...who can I pick on...." (chorus of "me"s follow) "Tannyr, can I pick on you?"
Tannyr: "Yeah...."
Teacher: "Now watch as I push on Tannyr's head with my hand. Does that hurt?"
Tannyr: "No."
Teacher: "Now, what would happen if I pushed on his head with this little thumb tack?"
Tannyr: "Ahh!"
Teacher: "Would that hurt more?"
Tannyr: nods quickly
Teacher: "What's the difference?"
Preston: "Yeah, there is no difference, so it shouldn't hurt."
Teacher: "What's the difference?"
Tannyr: "It hurts more...."
Teacher: "But I'm using the same force! So it shouldn't hurt more."
Preston: "Yeah, prove it!"