Apparatus: BB, tripod, asbestos wire, thermometer, 3 beakers, crucible tongs

Chemicals: Congo red, NaCl, anhydrous soda, white piece of cotton, dil. NaOH, Dil. HCl

Procedure:

Dissolve 0,2 [g] of Congo red in 100 [ml] water, heat to 60 [°C] and add 15 [g] NaCl and 0,5 [g] anhydrous soda.
If everything is dissolved give a piece of white cotton (or cellulose) to the dye-bath. Heat until boiling for about 30 minutes and turn the cotton with a glass rod from time to time.
Finally wash with cold water and allow to dry.

Additional procedure:

Give in one beaker dil. HCl and in another one dil. NaOH. Take a red piece of cotton
and dip it with crucible tongs into the acid.
Observation?
Now dip the cotton into the basic solution.
Observation?
By successive dipping you can produce stars and stripes!