Fill the jar about 1/4 of the way with water.
Add about 1 teaspoon white acrylic paint to the water and stir. It should look like milk. Add more paint if it doesn't.
Pour in the baby oil until it reaches the "neck" of the jar. Allow the paint and water to settle to the bottom.
Break the Alka-Seltzer tabs into small pieces and begin dropping them into the jar and wait for the snowstorm. Once it settles, you can do it again and again!