Example

Dress Rehearsal

Textbooks often include scientific or technical information written in words that can be re-written in the form of graphics: a chart or table. 

Your teacher has asked you to study a graph, translate it into words, and draw conclusions from it. The title of the graph is “Ozone Measurements at Halley.” You determine that the graph represents ozone measurements taken at Halley Research Station in the Antarctica. Neat!

According to the information on the side and bottom, measurements were taken during the months of August through April. The variables on the graph are two: the month and the total ozone measurement. Lines charted on the graph note that measurements taken were from 1957 to1972, and from 1999 to 2000. A red line on the graph represents the measurements from the first time period; a green line the second.

By examining the graphic, you note that the red line indicates that the ozone measurements varied from its lowest, 300 DU’s in August, to its highest, about 360 DU’s in November. In interpreting the green line, it would seem that the lowest level, in August, was 210 DU’s, and the highest was in January at 290 DU’s. You. Are. Good.

Most noticeable is the considerable dip in the green line; in October 1999-2000, ozone measurements were at their lowest. When compared to the measurements recorded on the red line during the same month from 1957-1972, a wide gap is obvious. This gap continued through mid-November. Scientists could conclude that during that time period, in 1999-2000, an ozone hole is sharply evident. The use of this graph helps scientists to establish trends in the loss of ozone levels. That might shoot a hole through the anti-global warming argument.

The other part of this standard takes the above task and reverses it. You are given information in text format from which you create a chart, table, or other graphic symbol. Let’s imagine that you are studying molecular shapes. You’ve been taught that the shape of a molecule often determines its physical and chemical properties. This model, known as the Valence Shell Electron Pair Repulsion model, or VSEPR, is based on an arrangement the minimizes the repulsion of shared and unshared electron pairs around a central atom.

The text asks you to imagine electrons as balloons that are inflated to similar sizes and tied together. Each of the balloons represents an electron-dense region. The forces in this region keeps other molecules from invading it. This is called a repulsive force. The balloons form a shape that minimizes interactions between the balloons. Head spinning yet?

You are asked to draw the following representations by translating the written word into a sketch:

• A set of two balloons connected at a central point, representing a central atom. A pair of balloons forms a linear shape. Draw a sketch of this linear bonding. Hint: This should appear as a line.
• A set of three balloons connected together form a bond angle. The angle formed by the central atom and two terminal atoms creates this angle. They are connected at one common point. Draw this bond. Hint: This should appear as a trigonal planar, or triangle shape.
• A set of four balloons creates a bond angle, connected at one common point. Draw this bond. Hint: This should appear as a tetrahedral, or three-D triangle, shape.

This standard has your mind working in opposite directions. Challenging, we know, but definitely a skill you’ll use often.

Source:

Buthelezi, Thandi, et al. Chemistry: Matter and Change. New York: McGraw Hill, 2008.

Quiz Questions