Magic Inks
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Oregon Museum of Science and Industry
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Learners write their initials by applying different clear "magic ink" solutions to separate pieces of paper and then "develop" the inks with other clear solutions. One "magic ink" is a sodium hydroxide solution that is "developed" by phenolphthalein, an acid-base indicator. The writing can be made to "vanish" again using a hydrochloric acid solution. Another "magic ink" is a potassium thiocyanate solution that is "developed" by iron chloride, forming iron thiocyanate ions that appear red. Commercially available "Magic Pens" are also used to help learners understand how they work. For safety reasons, this activity works best as a demonstration for younger audiences.
- 30 to 45 minutes
- Under 5 minutes
- $1 - $5 per group of students
- Ages 14 - adult
- Activity, Demonstration, Experiment/Lab Activity
- English
Quick Guide
Materials List (per group of students)
- Five 100-ml plastic storage bottles
- 5 large test tubes with rack
- 5 one-hole stoppers
- 5 non holed stoppers
- cloth tipped swabs (keep 20 on hand)
- 100 sheets of scrap paper, approximately 2 in. by 2 in.
- Phenolphthalein (an indicator; keep 15 g on hand)
- Five 250-ml plastic beakers
- Sharpened pencils (keep four on hand)
- Magic pens (CrayolaTM Secret Writers or GaltTM Magic Pens) (keep three on hand)
- Colored developer pens (CrayolaTM Secret Writers or GaltTM Magic Pens) (keep eight on hand)
- 95% C2H5OH (ethyl alcohol or ethanol) (keep 2 liters on hand)
- FeCl3 (ferric chloride) (keep 25 g on hand)
- KSCN (potassium thiocyanide) (keep 25 g on hand)
- 1M HCl (hydrochloric acid) (keep 500 ml on hand) — OR — keep 500 ml concentrated (12.1M) HCl on hand
- 1M NaOH (sodium hydroxide) (keep 500 ml on hand) — OR — keep 100 g solid NaOH on hand
Subjects
- Engineering and Technology
- Engineering
- Chemical Engineering
- Engineering
- Physical Sciences
- Chemistry
- Chemical Reactions
- Acids and Bases
- Solutions
- Chemistry
Informal Categories
- Toys
Audience
To use this activity, learners need to:
- see
- see color
- read
- touch
Learning styles supported:
- Involves hands-on or lab activities
Other
Components that are part of this resource:
This resource is part of:
Access Rights:
- Free access
By:
Rights:
- All Rights Reserved, Oregon Museum of Science and Industry, ©1997
Funding Source:
- National Science Foundation
