This is a chemical change. The bubbles are carbon dioxide which was caused by a chemical reaction. To demonstrate separating milk into its solid and liquid parts, let the children or group leader fill the baby food jar with fresh milk. Students will add 2 tablespoons of vinegar and stir. Allow the jar to sit for two to three minutes.
Milk is a mixture of liquids and very tiny particles that are spread throughout the liquid.
Vinegar causes the small undissolved particles to clump together, forming a solid called curd. The liquid portion is referred to as whey. The learner may also complete a data chart.