Object: An aspirin.

Good morning, boys and girls. Today we are going to show you something that I am sure is difficult to understand, and must have been very difficult for people a long, long time ago to understand. Let’s suppose that you have a headache. The pain is fierce and you think that your head is going to drop off if something isn’t done. Show me where you think that it would hurt if you had a headache. [Let them show you.] It would hurt your head. It wouldn’t hurt your stomach or your throat or your mouth, but it would hurt right up on the top, front, or back of your head. Are you sure? Are you positive? All right, we know where a headache hurts.

Now I want to show you what s…