Physical and Chemical Changes Physical Change Physical change

Physical and Chemical Changes

Physical Change Physical change is a change that occurs that does not change the identity of the substance A change in which matter looks different but is still the same matter. A change that affects the size, shape or color of a substance but does not affect its composition

EXAMPLES OF PHYSICAL CHANGES • • • Cutting paper Mashing potatoes Painting a wall Breaking glass Melting marshmallows Molding clay Water freezing Water boiling Thawing meat

A physical change alters the form of a substance, but does not change it to another substance. Making Orange Juice

Chemical Change Chemical change is a change that occurs causing the identity of the substance to change. Examples include: >Burning wood >Digesting food >Potassium reacting with water A chemical change can also be called a chemical reaction. Ø

Examples of Chemical Changes Wood burning to ash and smoke (a new substance is formed) Iron rusting Marshmallows burning Apple rotting Toasting bread

. When a substance undergoes a chemical change, it is changed into a different substance with different properties Example: Baking a Cake

Indicators of a Chemical Change Indicators of a chemical change can include: v. Light is produced v. Heat is either absorbed or produced v. Gas is produced v. There is a change in color v. Formation of a precipitate

Differences between physical and chemical changes With a physical change, the item can be change back to its original form With a chemical change, the item cannot be changed back to its original form

IS IT A CHEMICAL OR A PHYSICAL CHANGE Type of Change Physical Chemical Melting ice Burning wood Souring milk Wadding up paper Rusting metal Corn Starch and Water Corn Plastic Adapted from: www. dpi. state. nc. us/docs/curriculum/science/units/. . . /8 unit 2 pt 2. ppt

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