Teacher Notes on Description-Writing Exercises

Exercise 1: The paper clip

Context for this case:

Prerequisites:

One paper clip per student.
Paper clip illustration (see 2(B) for tips).
Description case with short or long prompts.

Cognitive Apprenticeship Features:

Externalizes good-description features.
Models role recognition for each feature.

Supporting References:

Good description guidelines.
H. Petroski, Evolution of Useful Things (optional).

Relevant CA Content Standards

Goal:: To promote role recognition by having students actively identify the parts of an adequate technical description (of a paper clip) and state why each part is included.
Strategy:: This is the first of several exercises (see also Exercise 2 and Exercise 9) in which students learn how to build a good technical description by analyzing the parts of an already written description and identifying the role that each part fills. The described object is familiar (a "Gem-style" paper clip), but with some unappreciated complexities.

(1) MOTIVATION:
I begin by pointing out that making your own paper clip is hard. Starting with a straight length of steel wire and pliers, it is very hard to successfully craft even one adequate clip, much less dozens of identical clips. A machine is needed (pictured at www.alteich.com/tidbits/still.gif, for example), and hence a very specific description of the output wanted from that machine.

(2) BACKGROUND:
Furthermore, many different paper-clip shapes have been conceived and actually tried since the first clips were invented at the end of the nineteenth century. Henry Petroski devotes Chapter 4 (pp. 51-77) of his Evolution of Useful Things (New York: Vintage Books, 1992) to the competing early forms of paper clip, their refinement, and their varied engineering properties. His book not only provides entertaining historical perspective on a familiar invention (and the design choices that it embodies) that you can share with your students, but it provides two very helpful illustrations as well.
(A) Contrast Class.
On p. 67, Petroski reprints the paper-clip illustrations (line drawings) from the 1909 and the 1934 editions of Webster's New International Dictionary. Each edition shows five very different clip designs, some still in use today, but only the 1934 edition shows the "Gem-style" paper clip now recognized as the standard shape. I use an enlarged copy of this figure to introduce students to the idea that a good description reveals the shape and parts of an object in a way that contrasts them with the many alternative shapes and parts that the object might have had (or did previously have) instead. (This technique of describing "against a contrast class" applies widely; see the elaboration in the notes on Exercise 0, Strategy, Part (4).)

(B)Model.
The color cover of Petroski's book (available freely online at images.amazon.com/images/P/0679740392.01.LZZZZZZZ.jpg even if you don't have the book itself) features a large photograph of one Gem-style paper clip perched on the tip of a human finger. The details are clearly visible and the simple visual comparison (with the finger) reveals at a glance the size and proportions of the clip to be described. You could almost label this image for use as Figure 1 with the description, although I simply photocopy one actual paper clip at 400% life size (with each bend labeled (a) to (c) from outside to inside) to make that figure.

(3) TARGET TEXT:
The student version of the paper clip description ("description case 1" below) contains the target text in the left column, divided by sentence (or very short paragraph), with scaffolding prompts (for key description features and their roles) in the right column. This lets you introduce a simple explicit technical description and focus student attention on what each part of the text contributes to the description's success (how each part helps the reader).

(4) SIGNAL HUNT:
To make an early, active connection between the description-writing guidelines and this sample description text, I ask students to read the text carefully and circle every reader signal that they find. Reading any text carefully enough (and more than once) so that they notice individual reader signals is a novel process for many students (and especially helpful for ESL students) . They must pay attention to the (last third of the) guidelines and to the role that specific text phrases play, and your commentary can help them recognize that a good description contains many signals installed by the writer just to help the reader follow and understand the text better. Among the most obvious here are the many labeled references to Figure 1 as well as the list of loops (first, second, third...) with parallel phrases for parallel physical parts.

(5) ROLE RECOGNITION:
With this signal recognition as a warm up, I then turn attention to the other description features. Confident students can write down their response to each prompt (right side) and then compare answers. Many students will need overt modelling of this general feature-recognition process, however. You might find it more helpful to distribute the fully annotated version of Exercise 1 rather than the student version (with prompts only) and then tour the exposed answers, discussing the contribution of each identified feature to the usability of the overall description. This shows more concrete cases of the description-writing guidelines in action. And it again reinforces the idea that in a good description no part of the text is idle; every part works:

This is indispensable ground work for the realization that the writer is responsible for making every part work.
This is a natural way to acquaint students with the idea that when they write descriptions, making every part work (for their readers) falls on them.
Role-recognition exercises like this also build up each student's general cognitive maturity so they can learn well from other examples by spontaneously "self-explaining" what each feature of the example contributes.
Together, activities (4) and (5) "reveal the magic" behind building an effective description: it is never just a jumble of technical terms, but rather a carefully crafted web of specific reader-support features.

Case:

Student version:


Description Case 1:  Paper Clip

     Description

A "Gem-style" paper clip is a            FEATURE:
length of stiff steel wire bent
into three flat, nested loops            WHY:
(Fig. 1) to hold sheets of paper
together when they are inserted
between the loops.

The wire is a 1-mm-diameter
steel cylinder that is 10 cm             FEATURE:
long.  It is bendable in the             WHY:
fingers but stiff.

The first loop (a) is a smooth,
U-shaped turn to the right
that starts 2 cm from the
outermost end of the wire.

The second loop (b) is a                 FEATURE:
U-shaped turn to the left                WHY:
that starts 3 cm farther
along the wire and has a                 FEATURE:
diameter just small enough               WHY:
to fit snugly within the
first loop.

The third loop (c) is another
U-shaped turn to the right
that starts 2 cm beyond (b)
and has a diameter just small
enough to fit snugly within
the second loop (as well as
the first).

The wire in each inner loop              FEATURE:
touches and runs parallel to             WHY:
the outer loop that wraps
around it.  All three loops
lie in the same plane, and
pushing them out of that
plane just enough to slide
several sheets of paper
between them makes the paper             FEATURE:
clip act like a spring and               WHY:
squeeze the sheets together.

Annotated version:

Description Case 1:  Paper Clip (Annotated)

     Description                                  Analysis

A "Gem-style" paper clip is a            FEATURE: Overview
length of stiff steel wire bent
into three flat, nested loops            WHY: (1) show framework
(Fig. 1) to hold sheets of paper
together when they are inserted               (2) show purpose
between the loops.

The wire is a 1-mm-diameter
steel cylinder that is 10 cm             FEATURE: contrast (implicit)
long.  It is bendable in the             WHY: reveal design decisions
fingers but stiff.                            (1) vs. ribbon or braided wire

The first loop (a) is a smooth,
U-shaped turn to the right                    (2) vs.  V-shaped turn
that starts 2 cm from the
outermost end of the wire.

The second loop (b) is a                 FEATURE: order (spatial)
U-shaped turn to the left                WHY: easy to follow
that starts 3 cm farther
along the wire and has a                 FEATURE: specifics
diameter just small enough               WHY: show relations among parts
to fit snugly within the
first loop.

The third loop (c) is another
U-shaped turn to the right
that starts 2 cm beyond (b)
and has a diameter just small
enough to fit snugly within
the second loop (as well as
the first).

The wire in each inner loop              FEATURE: specifics
touches and runs parallel to             WHY: show relations among parts
the outer loop that wraps
around it.  All three loops
lie in the same plane, and
pushing them out of that
plane just enough to slide
several sheets of paper
between them makes the paper             FEATURE: comparison
clip act like a spring and               WHY: reveal role of parts
squeeze the sheets together.

Note:

This exercise most closely supports the following 1998 California English-Language Arts content standard(s).
Reading:
Grade 5--"Understand how text features make information accessible and usable" (p. 28).
Grade 7--"Understand and explain the use of a simple mechanical device..." (p. 43).
Grade 11/12--"Analyze both the features and the rhetorical devices of...public documents" (p. 66).
Writing:
Grade 8--"Write technical documents...use formatting techniques to aid comprehension" (p. 51).

Contact: T. R. Girill trgirill@acm.org