Unit II—Part 2

Concept of ChangeChange: the act of altering a substance

Physical ChangePhysical change: a change that occurs that

does not change the identity of the substanceMelting ice(change in state or phase)

Freezing Kool-aidTearing paperBoiling water (same as melting ice)

Chemical ChangesChemical change: a change that occurs

causing the identity of the substance to changeBurningDigesting food Reacting with other substances(give an example per reviewer)

A chemical change is called a chemical reaction

Chemical Changes Cont’dIndicators of a chemical change:

Evolution of light Evolution of heat Evolution of a gas Color change Formation of a precipitate

Is it Physical or Chemical?

Change Physical Chemical

Melting cheese

Burning wood

Milk souring(Do all students relate to this?)

Wadding up paper

Bicycle rusting