SNC2D/2P Chemical Reactions/Chemical Reactions and their Practical Applications Teacher Demo: Invisible Ink Topics Timing properties of acids and bases preparation: 10 min pH demonstration: 10 min Specific Expectations SNC2D A1.1 formulate scientific questions about observed relationships, ideas, problems, and/or issues, make predictions, and/or formulate hypotheses to focus inquiries or research draw conclusions based on inquiry results and research findings, and justify their A1.10 conclusions C3.7 describe how the pH scale is used to classify solutions as acidic, basic, or neutral (e.g., a solution with a pH of 1 is highly acidic; a solution with a pH of 7 is neutral) SNC2P A1.1 formulate scientific questions about observed relationships, ideas, problems, and/or issues, make predictions, and/or formulate hypotheses to focus inquiries or research A1.10 draw conclusions based on inquiry results and research findings, and justify their conclusions C3.5 describe how the pH is used to identify the concentration of acids and bases Introduction In this demonstration, a chemical reaction is used to make a hidden message visible. The demonstration illustrates an entertaining application of chemical reactions in toys and everyday objects. It is also an interesting way to start the discussion of acids and bases, the pH scale, or acid–base indicators. Invisible ink has been used in espionage to send messages that cannot easily be read by enemies. Materials chemical safety goggles small bottle of phenolphthalein solution lab coat or apron cotton swabs or thin paint brush protective gloves paper towels or plain paper vinegar (5% acetic acid, HC2H3O2 (aq)) 3 spray bottle(s) window cleaner (with ammonia) or household tape ammonia Safety Considerations Provide MSDS sheets for all chemicals used.
SNC2D/2P Chemical Reactions/Chemical Reactions and their Practical Applications Teacher Demo: Invisible Ink Topics properties of acids and bases pH Timing preparation: 10 min demonstration: 10 min Specific Expectations SNC2D A1.1 formulate scientific questions about observed relationships, ideas, problems, and/or issues, make predictions, and/or formulate hypotheses to focus inquiries or research A1.10 draw conclusions based on inquiry results and research findings, and justify their conclusions C3.7 describe how the pH scale is used to classify solutions as acidic, basic, or neutral (e.g., a solution with a pH of 1 is highly acidic; a solution with a pH of 7 is neutral) SNC2P A1.1 formulate scientific questions about observed relationships, ideas, problems, and/or issues, make predictions, and/or formulate hypotheses to focus inquiries or research A1.10 draw conclusions based on inquiry results and research findings, and justify their conclusions C3.5 describe how the pH is used to identify the concentration of acids and bases Introduction In this demonstration, a chemical reaction is used to make a hidden message visible. The demonstration illustrates an entertaining application of chemical reactions in toys and everyday objects. It is also an interesting way to start the discussion of acids and bases, the pH scale, or acid–base indicators. Invisible ink has been used in espionage to send messages that cannot easily be read by enemies. Materials chemical safety goggles lab coat or apron protective gloves vinegar (5% acetic acid, HC2H3O2 (aq)) window cleaner (with ammonia) or household ammonia small bottle of phenolphthalein solution cotton swabs or thin paint brush paper towels or plain paper 3 spray bottle(s) tape Safety Considerations Provide MSDS sheets for all chemicals used.
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