Your task is to work with your team to investigate the ice balloon and find out as much as you can about how it behaves---in and out of water, and when you do different things to it. You can, for instance
Make notes of what you do and of your questions. Each person should be responsible for writing down their own questions.
Write one question per card, and remember to write clearly. Store the cards in a central place on the table for later use.
This is a brainstorming process, so do not stop to edit questions. Write down all of your questions, even those that might be quickly answered.