Page 356 - Between One and Many The Art and Science of Public Speaking

Chapter 12 Using Media in Your Speech 323

media than others. Ask yourself, “What is the best possible way to convey what
I hope to communicate to my audience?” To answer this question, consider the
following kinds of visual information, which are especially well suited to the
contemporary presentational media at your disposal.

Diagrams and Drawings

Sometimes a diagram or drawing will serve your purpose better than a photo-
graph. Diagrams are a good way to represent the parts of an object. For exam-
ple, a cutaway drawing of a fi rearm can be used to explain its functional parts,
and the diagram—unlike a real gun—is neither illegal nor potentially dangerous.
In Chapter 1, we used a diagram to illustrate an abstract concept, the communi-
cation transaction.

Charts and Graphs

Often a speech calls for a particular kind of visual representation of numbers.
Information such as the range of starting salaries among recent college gradu-
ates with different majors or the median wage for different occupations are best
explained and understood when given visual life. Charts and graphs are helpful
in this regard. Three types of charts and graphs particularly useful for depicting
statistical information are pie charts, line graphs, and bar charts.

Pie Charts

A pie chart is a circular chart that divides a whole into several parts, each repre-
pie chart
sented by a slice of the circle proportional to its share of the whole. In Chapter 8
A graphic often used to
(Exhibit 8.3) we showed a typical pie chart, which represents the percentage dis-
show proportions of a
tribution of cooking methods. The advantage of pie charts is that they simplify known quantity.
and dramatically illustrate the relative proportions of parts of a whole.
Line Graphs

Whereas pie charts are good for showing proportions, a line graph shows nu-
line graph
merical data as a series of points connected by a line. Line graphs are conve-
A graphic used to show
nient for showing changes over time; for example, Exhibit 12.1 shows changes points in time.
in population growth in the U.S. (both actual and projected) from 1950–2050.
By using two or more lines with different colors, you can also show how two or
more things compare across the same time period. Thus, if you want to compare
spending on schools with spending on defense over the past 10 years, a line
graph with two lines works well.

Bar Charts
A bar chart uses fi lled-in vertical or horizontal bars to represent various num- bar chart
bers, as shown in Exhibit 12.2. By grouping two or more bars or by color- coding A graphic used for com-
them, you can compare two or more categories. For example, the bar chart paring data side by side.
in Exhibit 12.2 compares binge drinking and marijuana use by age and sex
over time.