TheHangedFrog

I do adult education for a class called Haz-Woper, full name Hazardous Waste Operator. Teaching people how to deal with hazards on the job including storage and cleanup. I have been looking for an example of polymerization. I know most polymer creation is actually hazardous, alot of exothermic heat and fumes.. BUT is there anything that might be able to be used, combine 2 chemicals and get a resulting product that is rapidly expanding? I am not interested in the vinegar and baking Soda or the fake snow compounds, but something like making crude polystyrene foam, or a jell or something that grows over the container and runs down the edges.. As little hazard as possible would be the best for me. Having to clean up a real hazardous material in class would not go over well with my bosses. Thank you in advance for any useful answers.

I am not looking for answer like win sweepstakes, I have called several times to book tickets, and got someone on the phone within min, of sales opening, and the first 30 or 40 rows are sold out.