Making Butter You Will Need: heavy cream jar with a tight cover a marble Directions: Put the cream in the jar with the marble. Screw on the cover and make sure that there are no leaks. Shake the jar in a figure of eight motion. While the cream is still runny, you will be able to hear the marble. As the cream thickens, the sound disappears. Butter will form all of a sudden; drain the butter from the buttermilk and pack down firmly. What Happened? Why does the process of making butter depend on the fat molecules suspended in the liquid? Cream is an emulsion of fat in water. The fat droplets are held in suspension by the milk protein. When you make butter from cream, you force the fat droplets to join together. This process is called coalescing. Consumption: Serve the butter on toast and sprinkle with cinnamon. Best served with hot chocolate.

Bibliography Cobb, V. Science Experiments You Can Eat (New York: Lippincott, 1972).