Heat slowly and stir until the mixture thickens and lumps form. What happens The milk changes. A thick substance forms on the bottom of the pan and a watery liquid is found on the top. The acidic chemicals in the vinegar react with the organic milk chemicals. The milk becomes sour when mixed with the vinegar and separates.
White glue is made from casein of in curds as well as some cheeses.
Extensions Make a Plastic Toy Pour off the liquid and form the milk lumps into different shapes or toys. Allow the newly shaped toy to harden for two hours in open air. Colour the plastic toy with paints for an added effect. Make Glue Put the curds in a jar. The mixture bubbles and changes into a gooey white glue.