These are finite task opportunities, not proof of mastery. Record what was attempted and what support was used.

• Reversibility alone is not a reliable test for distinguishing physical and chemical changes.

• Laboratory performance, measurement uncertainty and real reaction observation are not assessed.

• Finite task opportunities, not learner mastery or universal canonical coverage.

• Use the supplied materials on screen or print one current sheet; physical printing can vary.

• Record the actual response and assistance; completing a task does not establish mastery.

Paper/screen reasoning only. Do not burn toast, light gases, mix chemicals, heat liquids or seal a reacting container. The atom reaction and mass records are explanatory models, not procedures. Do not eat or taste materials for this lesson. A real conservation experiment involving gases or burning belongs in an appropriately equipped laboratory with qualified supervision; this packet does not provide that protocol.

Record the learner’s actual words or work, task ID and any help. Do not prefill success. Allow oral, pointing or written responses as appropriate; oral independent reasoning is not automatically supported. Copied/scribed text is not independent composition or handwriting. No name, account, upload or real family record is required.