Jonathan Gomez

Professor Blocker

Public Speaking Hybrid (WINTER 2013)

COMM 220-003/CRN 60772

Concept Applications #2

One type of supporting material used by Robert Cannon was the use of comparison, the process of associating two items by pointing out their similarities. He used an apple for a literal comparison showing its similarity in shape to planet Earth. He showed how the apples indentations at top and bottom are similar to the effects of the magnetic fields in the North and South Pole. He then cut the apple in half to demonstrate by comparison the amount of Earth that is core just as the apple is mostly the fruit and not the skin.

Another supporting device used by cannon is the use of testimony, the use of an authoritative source to clarify or prove a point. He quotes magazines, videos and scientists extensively. For example when he references Mario Vicuso who is quoted in the PBS program Nova, the scientist is introduced by Cannon as “one of NASA’s foremost authorities”.

Cannon used visual aids in more than one instance. He used the apple as previously mentioned as both a literal comparison and metaphor. Later in his speech he used an illustration of the Earth and its magnetic fields. The first presentation aid was more effective than the second. The illustration was more of a dramatic demonstration of his material rather than a clarification of any point he was making. More information on the result of the effect of the polar