This lab uses basic household materials to have students explore, compare, and contrast physical and chemical changes. There are also questions about heterogeneous and homogeneous mixtures. For the first component, students mix lemon juice, water, and vegetable oil and evaluate what kind of change occurred. Then they mix chocolate syrup and milk and make observations before adding lemon juice. The curdling of chocolate milk makes a great finale and is a very memorable way to distinguish physical and chemical changes.
This activity supports NGSS through cross-cutting concepts of cause and effect and stability and change, and the science and engineering practices of developing explanations. It also supports disciplinary core ideas under Physical Sciences.