In Fleet class today for Science, the children have been looking at reversing the state of matter.
In this experiment, Anthony takes some freshly boiled water and pours the water into a jug. The jug is then covered with a conductor of heat; in this case, aluminium foil. Pieces of chocolate are then placed on top of the foil. In a short amount of time, the chocolate starts to melt. The solid state of the chocolate is becoming a liquid due to a chemical reaction. By introducing heat, the physical state of the chocolate is changed from a solid to a liquid.
Later, Anthony then placed the now melted chocolate into a freezer. After a short amount of time, the liquid state of the chocolate reversed back to a solid state due to the drastic drop in temperature.