Kind of a tough topic for a Theater class, whether it was pre-chosen topic or you chose it, you'll have a strong task at hand. For the age range you're speaking to, I don't know if using tough scientific jargon will make a strong impression but I suppose whatever you can muster will be ok. Then you also have to be careful if you come across too preachy, you may end up not doing well on the assignment. I'm not saying to water down the message but use the best method for the limited time you will have. Maybe I'd summarize it this way:
-Law of thermodynamics....must have had a beginning, evolution would suggest the big bang creates chaos. In a Way of the Master series, Ray Comfort says to ask an evolutionist, if you have an empty garage, see about waiting 10 years to see if a Mercedes will form, then 20, then 100, etc. and evolutionists suggest that billions of years have occured to create the beautiful world around us. Chaos/big bang creates disorder, not order
-Building/Painting....How do I know there was a Painter? The Painting is evidence of a Painter...a building is evidence of a builder..creation is evidence of a Creator
To lighten the mood of the talk, maybe I'd do the following. This was done by Ray Comfort during a speech and he talked about the evolution of the soda can. Millions of years ago, there were a mess of chemicals, over time the chemicals formed together to make a soda, a metal can eventually formed around the soda, paint slowly appeared around the can, and a tab later developed for ease of access. I think if you start off with something like that, to make it kind of comical, then go into the serious, may get people thinking about how absurd evolution (and atheism) really are. Obviously, you would want to find the exact dialogue Comfort uses and cite the soda can example that he gave behind the story. I hope it goes well
Sean