MATERIALS:

Baking Soda,
Water
Cotton swabs
Small cups
White paper
Paintbrushes
Blow dryer
Purple grape juice

INSTRUCTIONS:

1.  Combine 1 tablespoon of baking soda and 1 tablespoon of water in a cup.

2.  Dip Cotton swabs into the mixture and make designs on sheets of white paper.  

3.  When papers are completely dry, paint over the papers with purple grape juice.   The designs will change from being invisible to visible.

Note:  Using a blow dryer will speed the drying time