Enhancing the Learning Value of Worked Examples

There is an often-told story about a preacher who accompanied his sermon on the vices of alcoholic drinks by a demonstration. He took a few live worms and dropped one each in different bottles containing water, milk, fruit juices, and alcohol, whereupon only the worm dropped in alcohol stopped wiggling and died. The preacher expectantly looked towards the audience and asked them what lesson they learned from the demonstration. The old drunk in the back row raised his hand and offered, If I drink alcohol, I will not have any worms in my stomach. © 2006 IEEE.