Pour a thin layer of milk in a shallow pan. 2. Have the kids add drops of food coloring all around in the milk. 3. Then the kids will pick up a cotton swab and dip it in the dish soap. 4. Then put the cotton swab in the milk - pressing it down in one spot and holding it there for about 15 seconds. Watch what happens! There will be lots of ooohs and ahhhs. And maybe even some questions about what it is happening.