Note: This plan may or may not get used, but (in my opinion) is a simpler, more elegant plan.
Exposition: Introductions (Name, occupation, should take about 10-15 secs)
Rising Action: Brief summary of the Challenger disaster
Climax: Act out Feynman’s O-ring experiment
Falling Action/Resolution: Just sit down for effect. It’ll have to be on the floor, as a chair would be too large a prop.