Read the evidence

The station display includes water, ice, a steel spoon, a wooden block and baking soda. Physical properties can be observed or measured without changing a substance into a different substance. Examples include state, colour, texture, density and melting point. Chemical properties describe how a substance can change into new substances, such as flammability or reacting with another substance. A change of state, such as ice melting into water, is physical: the substance remains water. Bubbling during a reaction can be evidence that a gas has formed, but bubbles alone do not prove that every process is a chemical reaction.