VC2S6U04

changes to substances may be reversible, in which case the substance may be recovered, or irreversible, in which case new substances are formed; for most substances a change of state or dissolving in water is reversible, while irreversible changes include cooking and rusting

• discussing what makes a change reversible or irreversible, using everyday examples
• examining the substances produced in cooking and rusting, and comparing them with the original substances
• comparing how the amount of heat energy added may affect whether a change in state or an irreversible change occurs, such as when heating chocolate
• investigating solubility by observing which common substances dissolve in water, for example sand, salt, sugar, oil, metals and plastic
• describing how dissolved substances are reclaimed from solutions
• exploring how reversible changes can be used to recycle materials
• investigating Aboriginal and/or Torres Strait Islander Peoples’ knowledges of reversible processes such as the use of resins as adhesives in toolmaking to allow repair and reshaping, and of irreversible processes such as when using fuels for torches