Question

boiling water producing a lot of bubbles is _
physical change
chemical change

Explanation:

In a physical change, the substance's chemical composition remains the same. When water boils and produces bubbles, it is changing from the liquid - state to the gaseous state (water vapor), but the chemical formula of water ($H_2O$) does not change. In a chemical change, new substances with different chemical compositions are formed. Since boiling water only involves a change of state and not a change in chemical composition, it is a physical change.

Answer:

physical change