Some of the concepts discussed:
Relative size of bubbles (Which one is bigger?)
Cause and effect (How did you make bubbles that big?)
Opposites (Sucking vs blowing on the straw)
Scientific inquiry (How do explore something new?)
How do scientists use tools?
Using our senses to gather information about objects (Tell me about your bubbles)
Making simple observations/predictions and explanations (What will happen if you...)