Pirate science activities: Invisible ink

A pirate theme is exciting for teaching science lessons. Swashbuckling and salty talk will add to the fun of pirate science activities. Invisible ink can make secret messages for kids while introducing some chemistry. [Be sure to check out compasses in Part 1 of pirate science experiments.]

Teaching with a theme works well with organizing science lessons into stations. When you don’t have enough resources for every group of children to do the same lab, stations can be the solution. Using stations is also a great differentiation technique. See Part 1 for my tips for organizing station labs.

Safety note: Be sure to explain safety precautions to children. This experiment uses a weak acid and base. Safety goggles should be used. Avoid eye contact and wash hands thoroughly. Disclaimer: All information provided on this site is for entertainment and education purposes only. Using any information from thecasabouquet.com is at your own risk.

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Invisible ink instructions

• Start with one tablespoon of baking soda. Add 1 tbsp of water and mix.

  

  

  
  
• Write a message on a piece of white paper by dipping a writing tool in the mixture and “painting” the words. (Cotton swab, toothpick, or paintbrush will work.) Let the invisible ink dry.
• Now you will need to give the message to someone to read. They will need a way to make the message appear.
• Use a lamp with an incandescent light bulb as a heat source. What color does the “ink” become? How long does it take to for the message to show? [With adult supervision, you may want to try an iron.]
• Write another message on a clean sheet of paper and allow it to dry. Use some grape juice concentrate and paint the paper with the juice. What color is the message? What color is the painted paper?

What does the heat do to the baking soda to make it appear? Grape juice is a weak acid and baking soda is a base. What is the juice and baking soda reaction? What other substances can you try to make the message and make the message appear? Can you find the pH of these different substances?

Supplies

• Baking soda
• Water
• Grape juice concentrate
• Paintbrushes (small round and large flat)
• Cotton swabs or toothpicks
• Small dish or cup
• Tablespoon
• Incandescent light bulb
  • iron could be more successful
• Other juices (acids): orange, lemon, apple
• Other bases: soap, ammonia, antacids
• pH paper or Vernier LabQuest with pH Sensor
• paper or notebook for recording results, pen

What is the science?

Content: matter and its interactions, conservation of atoms, conservation of mass, acids and bases, oxidation

C₄H₆O₆ + 2 NaHCO₃ → Na₂C₄H₄O₆ + 2 CO₂ + 2 H₂O

The main acid in ripe grapes is tartaric acid. Tartaric acid with baking soda makes sodium tartrate, carbon dioxide, and water. When grape juice is painted on the paper with baking soda writing, the grape juice reacts with the baking soda. If you try the experiment with lemon juice, the main acid is citric acid. These compounds all contain carbon. When heated, the carbon is released and can oxidize in a reaction with the air.

Resource links

• http://www.scientificamerican.com/article/bring-science-home-invisible-ink/
  • Invisible ink reveals cool chemistry from Scientific American
• http://www.kidzworld.com/article/3844-making-invisible-ink-appear
  • Making invisible ink appear from KidzWorld
• http://www.makeandtakes.com/3-secret-codes-to-try-with-your-kids
  • 3 secret codes to try with your kids from Make and Takes
• http://kidsactivitiesblog.com/26618/crayon-resist
  • Crayon resist: White crayon secret art (cool)! From Kids Activities Blog
• http://tinkerlab.com/invisible-ink-a-citrus-painting-experiment/
  • A citrus painting experiment from Tinkerlab
• http://howtosmile.org/blog/posts/avast-me-hearties%E2%80%94its-pirate-science
  • Avast me hearties from Lawrence Hall of Science
• http://blogs.scientificamerican.com/cocktail-party-physics/the-science-of-pirates/
  • A pirate’s life for me from Scientific American
• http://www.vernier.com/products/interfaces/labq2/
  • LabQuest 2 from Vernier Software and Technology
• http://www.hobsess.com/september-19-talk-like-a-pirate/#.Vkzc2t-rQ6g
  • September 19: Talk like a pirate from Hobsess blog
• http://inspiredbyfamilymag.com/2012/09/25/no-sew-captain-hook-costume-from-a-t-shirt/
  • Captain Hook costume from Inspired by Familia
• http://ncmaritimemuseums.com/beaufort/resources/blackbeard/
  • Blackbeard’s Queen Anne’s Revenge from NC Maritime Museums

Let’s talk story

pirate scientists

My friends Kelly and Jen love pirates as much as I do. This is the second in a series of pirate labs we put together. Here’s some of our pirate inspiration: Treasure Island, Peter Pan, Pirates of Penzance, Pirates of the Carribean, The Pirate Queen, and Jake and the Neverland Pirates.

In North Carolina, Blackbeard is “our” pirate (other states claim him, too!) Along with science, you can tie pirates to social studies. Other famous pirates: Barbarossa, Thomas Cavendish, Sir Francis Drake, Charlotte de Berry, Sir Henry Morgan, Black Bart, Stede Bonnet, Captain Kidd, Anne Bonny, Mary Read, Jean Lafitte, and Grace O’Malley.

I’ll be looking for comments below, or contact me at lisa [at] thecasabouquet[dot]com.