Hi. I am writing preschool science activities and would like to verify what the scientific principles behind them are. First example: when you put raisins in clear soda pop, exactly what causes the bubbles around the raisins to pop when they reach the top? Is it only the outside air pressure? Second example: when you blow through a film of soap to create bubbles, is it surface tension that holds the soap together around the air? And what exactly happens when they pop? Thank you.