Purpose: To inform the audience about tornadoes.
A. Attention getter: What can throw tractor trailers threw the air like matchbox cars, rip homes to shreds and travel at speeds near 400 MPH? B. Audience motivation: There are approximately 10 Air Force bases located in or very close to tornado alley. Knowing the different types of tornadoes and what to do if one occurred near you may potentially save your life. C. Credibility: I lived in the heart of tornado alley for 16 years and have personally experienced at least 30 tornadoes. D. Thesis Statement: The purpose of this presentation is to inform the audience on tornadoes. I will inform them on what a tornado is by definition, what causes a tornado, the types of tornadoes and tornado safety.
A. According to the Encyclopedia Britannica the definition of a tornado is a violent, low-pressure storm, relatively small in diameter but with very rapidly rotating winds and an intense updraft near the centre. B. What causes a tornado
i. The USA Today Information site states that tornadoes form in unusually violent thunderstorms when there is sufficient instability and wind shear present in the lower atmosphere. Meaning, severe thunderstorms are the first step in the creation of a tornado. ii. The same source defines instability in a thunderstorm as an unusually warm and humid condition in the lower atmosphere and cooler than usual conditions in the upper atmosphere. Wind shear refers to the wind direction changing and wind speed increasing with height. An example would be a southerly wind of 15 mph at the surface, changing to a southwesterly or westerly wind of 50 mph at 5,000 feet. iii. I mentioned in the introduction that quite a few Air Force bases were located in tornado alley. [VISUAL AID] More tornadoes occur in this area because cold air...