Reasons for Using Graphics
Graphics in written and oral reports are invaluable aids to your audience because they condense text, clarify relationships, and highlight patterns. Good graphics display the significance of your data (which may be more exactly displayed in a table) and allow the reader to follow your discussion. Drafting graphics may also be a very effective way to help you draft a long written report or oral presentation.
Common Graphics
Graphics commonly used in technical documents include the following:
Working drawings Diagrams
Tables Photographs
Bar graphs Exploded views
Line graphs Schematic diagrams
Pie graphs Flowcharts
Illustrations Timetables or Gantt charts
Working Drawings
Working drawings may be used to give detailed descriptions of the current state of your experimental apparatus and as common graphics in oral design reviews.
Working drawings may be highly detailed and may present exact specifications for the construction of apparatus. Identify working drawings with an explicit title and the date. Be sure to show tolerances and exact measurements and, if necessary, a scale of measurement on all figures.
Tables
Tables present data in a highly condensed form. Tables present data more exactly than a graph, but they do not readily display the trends within your data. (They should rarely be used in an oral presentation – rely on figures instead.)
Every table is identified in a written report by a number and a title, placed above the table. In contrast, the number and title of a figure in a report are usually given below the figure.
The parts of a table include
Title and number (above the table).
Boxhead, the horizontal region across the top of a table containing column headings with units of measurement clearly identified.
Stub, the vertical column to the far left of a table in which you list the various line headings that identify the horizontal rows of data in the body of the table.
Body, all the data, presented in columns below the boxhead, describing items in the stub. If you want the reader to see a comparison between any items in a table, then place those items close to one another.
If any table or figure is taken from another source, proper credit must be given in a source note below the table or figure.
Table 1. The volume of solution in ml delivered from a random sample of 1.00 ml capacity tuberculin syringes with Luer slip tips and 9.5 mm 27 gauge needles with intradermal bevels.
OBS |
GRADUATION |
|||||
|
0.05 ml |
0.10 ml |
0.15 ml |
0.20 ml |
0.25 ml |
1.00 ml |
1 |
0.0466 |
0.0895 |
0.1405 |
0.1949 |
0.2429 |
1.0012 |
2 |
0.0474 |
0.0998 |
0.1505 |
0.2033 |
0.2514 |
0.9994 |
3 |
0.0487 |
0.0972 |
0.1473 |
0.1978 |
0.2451 |
1.0052 |
4 |
0.0505 |
0.0935 |
0.1472 |
0.1978 |
0.2502 |
1.0016 |
5 |
0.0442 |
0.0935 |
0.1443 |
0.1982 |
0.2450 |
1.0031 |
--Seth Frisbie, The Determination of Total Dissolved Inorganic Carbon
in Pure Systems
Bar Graphs
Bar graphs display relationships among data by means of vertical or horizontal bars of different lengths. Sometimes a single bar of a set height is used to break down percentages of the whole, in much the same fashion as a pie graph.
Single Bar Graph
Single bar graphs visualize the effects of varying limiting conditions on one particular object of study, as in Figure 5, where heart rate is shown under various burden conditions of exercise.
Multiple Bar Graph
Multiple bar graphs visualize the different objects of study under one particular limiting condition, as in Figure 6, where three items are compared over time.
Stacked Bar Graph
Stacked bar graphs visualize various items as percentages of the whole for ease of comparison and contrast. Figure 7 is a single bar graph showing percentages of one particular object of study. (Compare this figure with Figure 11, a pie graph drawn from the same data.) Figure 2 is an example of a multiple stacked bar graph where various items are broken down into percentages of the whole for comparison.
