Solicit three volunteers and ask them to stand in the hallway away from the door until you signal them to return. While the volunteers are in the hall, ask students to take out a sheet of paper to write instructions for a magic trick that you will demonstrate. Tell them to watch closely as you repeat the trick several times. Ask students not to place their names on their instructions and not to ask any questions until the entire experiment is over.

          Before class you will need to tie the ends of a six-foot piece of rope to form a circle. To prevent students from copying the written instructions that follow, demonstrate the magic trick as you read these instructions silently:

1. Place the circle of rope around your neck like a necklace. (Click here to see Figure 6-9.)
   
   
2. Grab the right strand of the rope in your right hand and loop it once again around your neck, creating a double circle. Pull the rope tight so that a long loop remains on your chest. (Click here to see Figure 6-10.)
   
   
3. Next form an X by grasping the left stand of the rope with your right hand and crossing it to your right. This creates the appearance of a figure eight with the X in the center of the "8" at point D in the illustration.(Click here to see Figure 6-11.)
   
   
4. Grasp points A and B and fold the circle formed by the bottom of the eight so that point C rests under your chin. This forms one double-rope circle on your chest. (Click here to see Figure 6-12.)
   
   
5. Place your head through this circle by clasping both strands of rope at points E and F and placing both strands at H over your head. (Click here to see Figure 6-13.)
   
   
6. Announce to the class that you are either going to pull the rope directly through your neck or choke yourself. (It helps to practice!) Grasp any single strand of rope with both hands, grimace, and pull. The rope should pull free. If you slide your hands apart while holding the strand as you pull, you will create the illusion that the rope is penetrating you neck.
   
   

          After students have written their anonymous instructions, collect them and lay them out on a large table. Have the volunteers return to the class and ask each to pick one set of instructions. Then, ask volunteers to take turns reading their instructions aloud while attempting to perform the trick.

          Chances are that the volunteers will have difficulty. Explain to the class that they were tricked. Earlier, by having the class not ask questions, you reduced the chance that someone might pose the question "Can we draw pictures?" Such a question would have motivated everyone to think visually and improved their chances of creating clear instructions.

          Why the deception? The point of the experiment is to show that without images in the instructions (both verbal and graphic), the chances for clear communication are almost impossible.