Properties of Materials

Year 5 are investigating the properties of materials. At the moment, we are focusing on reversible and irreversible changes. Today, we carried out two experiments. Firstly, we added bicarbonate of soda to white vinegar and used a balloon to capture the carbon dioxide these substances produced. Then we made casein plastic, which was a substance popular from 1900 to 1945, used to make many household items, including buttons and combs. In order to do this, we added a few teaspoons of white vinegar to warm milk and then mixed them together. The milk curdled and we then strained it (using tights) to separate the liquid from the casein. We then moulded our pieces of casein individually and they have been left to dry and set, for 48 hours.