Masters of Illusion
By Daniel Menelly

Drawing convex and concave portraits can be a hilarious science activity and also helps to develop students' decoding skills.

If learning took the form of a vehicle, skills should be considered the gears that allow it to operate. Essential skills like keen observation and active listening are, to me, first and second gears in the learning process. Yet in the age of information, where the name and likeness of a product is typically repeated five to 10 times in a single short advertisement, students may "unlearn" the skills of active listening and keen observation. Each year I attempt to recover, calibrate and sharpen my students' essential skills with a series of simple sensory-based lessons that make use of their passion for optical illusions and special effects.

Spoon portraits. The most popular book in my classroom lending library is one about optical illusions. Recalling that gifted learners typically possess the ability to recognize certain patterns, decode ideas and "sort out" shapes and patterns readily, I designed lessons that would require these skills. The first is simple and inexpensive, yet stirs a great deal of curiosity (and humor) in my students by asking them to draw self-portraits of their faces as reflected in the outer, or convex, surface of a spoon.

The drawings, done in blue or black ink, easily transfer onto a slide using photocopier transparencies. After removing the names of students from each portrait, I project the resulting images onto a white wall in my classroom and ask the class to simply identify each other based on their convex, or distorted, images.

My students immediately set about restoring, in their minds, the attributes of each face. Lots of laughter and impromptu hypotheses often erupt. Several students focus on key visual clues others overlook, such as curvatures of eyebrows and jaw lines. That's precisely the skill I want to see. The students are required to inventory the visual information that is available to them and to base a decision on it.

Convex vs. concave. Students tend to connect the lesson to related events in everyday life. During a follow-up discussion, students may compare this simple lesson to a visit to a carnival funhouse. Some note that clothing purchased in stores often looks different at home and suspect that concave ("skinny") mirrors may be used to entice purchases. Others remind the class that convex mirrors creating images similar to ours are used in stores and parking garages for security. In later incarnations of this lesson, I rely on plastic "bubble" mirrors purchased inexpensively through a science catalog. Students work in pairs with a single mirror, where one student is assigned the convex portrait and a partner is assigned the concave portrait appearing on the opposite side of the mirror. The concave images tend to be even more alarming, but involve the same range of decoding skills to interpret.

I follow the spoon lesson with science lessons involving hand lenses and microscopes and carefully note the depth of my students' observations of simple and complex things like cells and feathers under magnification.

Lend me your ears. Interestingly, a few weeks after the spoon lesson on observation, my students ask for another similar lesson. My response is a lesson involving puzzles we hear, not see. I want the class to rely on a second, equally essential skill to decode information, so I offer a companion lesson involving an inexpensive recording of sound effects.

We begin by identifying simple sounds, such as a frog croaking or a window closing. Then, to require students to filter auditory information, I play combination sounds such as a barnyard of animals, arcade sounds or Spanish-speaking cowboys on horseback. I ask my students to specify clues that identify each sound, such as hooves clopping, certain words and other specific sounds. I play each sound twice, yet students often ask me to play them once, as a challenge.

Bonus features. "You want a challenge?" I'll ask, as I pull out a second recorder and proceed to play two unrelated sound effects simultaneously. "Hey, that's not fair!" one student is likely to protest. "You're right," I'll offer, "but isn't this what we do when try to read or do homework with the radio or TV on?" The self-assessment of personal study habits is a bonus to the sound effect lesson, but the key focus for my teaching is an examination of the group as active listeners.

The convex image and sound effects lessons are distant cousins of the beloved "mystery box" lesson, where students reach into a box to feel and identify certain shapes and textures. That particular lesson lends itself well to geometric forms, specific properties of matter and, for language class, descriptive skills for writers. It's one I often see replicated at home for pleasure, the hallmark of a great lesson.

The simple things. While I do have access to a wide array of sophisticated learning technologies and media, I sometimes prefer lessons stripped of gadgetry and elaborate outcomes. When addressing the essentials, I find the simplest lessons require students to look critically at an isolated skill and to improve upon it. Interaction between the class and teacher during these lessons presents some of the most spontaneous and uplifting moments of the term. The result is a bonding of sorts, a lowering of inhibitions and a deeper awareness of essential skills that serve students well as the year progresses and things gradually become more complex.

Daniel Menelly teaches science at the American School of Paris and is also tenured at the United Nations International School.

February, 2004, Vol.34, No.5