When my wife and I approached, Dr. Hazari was making clouds on the ground. As people drew closer, he warned those with sandals to stay back so they didn’t freeze their toes. I missed the beginning of the demonstration but I assume he was pouring liquid nitrogen on the ground. As it hit the cement, it immediately boiled and turned to vapor. Dr. Hazari explained that his clouds were similar to clouds in the sky.
Next, Dr. Hazari pointed out a piece of dry ice that was boiling in the bottom of a large graduated cylinder. He added different clear liquids to make the colors of the rainbow. The experiment was similar to a pH test. The colors changed as the solution became more acidic. Each color represented a different pH range.