Magic Christmas Colors Poster
Chemical Concept:
acids and bases
indicators
Materials:
iron (III) chloride solution (1 g FeCl3/100mL 0.1M HCl)
1% phenolphthalein solution solution (1g phenolphthalein / 50mL ethanol +
50mL H2O)
potassium thiocyanate solution (5g K4Fe(CN)6/ 95mL H2O)
1% sodium hydroxide solution (1g NaOH / 100mL)
2 household sprayer bottles
2 paint brushes, narrow
Watercolor paper (from art supply store)
Procedure
1. Immerse the paper in water; use a clothespin to secure the paper to a
hanger and allow it to dry.
2. For BLUE letters, write the words in 5% potassium ferrocyanide
solution. Allow to dry. When ready to use, spray the words with ferric
chloride solution.
3. For RED letters, write the words with 5% potassium thiocyanate
solution. Allow to dry and spray with the ferricchloride solution.
4. For PINK letters, write the words with 1% phenolphthalein solution.
Allow to dry and spray with 1% solution hydroxide solution.
5. If the signs are made up in advance, be sure to store them in a dry
place.
Safety
Check the MSDS for precautions and disposal.
Adapted from Element of the Week/ Teaching Tips