Physical and Chemical Changes How to tell the difference

Physical Change- physical properties change, but the substance is the same Change in what you see but does not produce a new substance Painting a house, cutting hair, ironing shirt, melting water/boiling water

Some physical changes are reversible, some are not Reversible—freezing & melting water, braiding hair Non-reversible—slicing a tomato, peeling an orange

Indicators of a Physical Change

It’s a physical change if It changes shape or size It dissolves.

It changes phase (freezes, boils, evaporates, condenses) It’s a physical change if... It changes phase (freezes, boils, evaporates, condenses)

Chemical Change Chemical Change- when substances react to form one or more NEW substances Look for permanent change in color, gas bubbles, leftover solid Non-Reversible

Indicators of a Chemical Change

It’s a chemical change if…. It burns Temperature changes without heating/cooling

It’s a chemical change if... It bubbles (makes a gas)

It’s a chemical change if... It changes color permanently It forms a leftover solid

Examples: Silver ring that turns green Rusting cars Copper pennies turning green Baking powder in cake – cake rises Vinegar and baking soda Adding vinegar to milk Lighting a match Explosion or burning of wood

What kind of change is it if someone... Tears up paper? Physical change Mixes salt and water?

What kind of change is it if someone... Burns paper? Chemical change Evaporates salt water? Physical change