Saturday, October 23, 2010

Happy Mole Day & Kid Friendly Experiment #2

Happy Mole Day to you all!!  You can read my little tidbit on Mole Day in my post from earlier this week.

On Thursday evening, I went to the monthly American Chemical Society meeting for the Columbus section.  We have one member who is extremely dedicated to all of the teaching & philanthropy that our section does, he is always bringing kid friendly demos or experiments to show us!  Since this year's theme is "Behind the Scenes with Chemistry" they have provided an experiment to make Iron Tannate ink, so kids can feel like they are writing like Harry Potter!  I got all of the following instructions from the National Chemistry Week "Celebrating Chemistry" newsletter (with my suggestions/changes in blue); you can find an electronic copy here.  Big caution to those who may choose to do this: THE INK CREATED IS PERMANENT AND WILL NOT WASH OUT OF CLOTHES!

Supplies needed:
  • 2 mugs, teacups or small glass bowls (you need to have something that won't get stained by coffee or tea)
  • Boiling water (for adults only to do please!)
  • 1 tea bag (black tea, which has more tannins for the chemical reaction)
  • 1 iron (ferrous) sulfate tablet (a supplement you can get from the grocery store)
  • Mortar & pestle (okay, most people don't have this lying around the house, you simply need something to crush the iron sulfate tablet into a powder)
  • Measuring cup
  • Small storage container (I'd recommend a glass baby food jar)
  1. ADULT: Put the black tea bag into your first mug, add 2 tablespoons of boiling water & make a very strong tea (removed tea bag when finished).
  2. Label your small storage container with  your name, the date, & "Iron Tannate Ink"
  3. If your iron sulfate tablets are coated, wash the coating off under running water & then dry the tablet.
  4. Crush the iron sulfate tablet using your mortar or pestle (they suggest a glass jar in a mug as a comparable replacement) into a powder.
  5. Add the iron sulfate powder to the tea; watch for it to go from a brown liquid to a dark brown or black liquid.
  6. Transfer to your labeled storage container to be used with a fountain ink pen or quill (if you want to feel like Harry Potter).
About the reaction:
When tea is brewed, it is brown because of "tannins" (this compounds are also found in wine).  Tannins react with the iron from the iron sulfate tablets to form iron tannate which is actually a solid.  The solid particles are so small they stay suspended in the liquid very easily.  Small solid particles suspended in a liquid can be called a suspension concentrate.  The ink will get darker as it reacts with oxygen in the air, and if you use the ink to write on paper it may actually eat away at the paper after many years.

Since you are using food grade materials and no preservatives, your ink may grow mold eventually.  Throw it away when this happens.  Within the newsletter (using the link above) are instructions to make colorful or aged-looking paper.

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