Physical & Chemical Changes

•Is melted butter still butter?•Is soured milk still milk?•Are the ashes from a fire made of the same “stuff” as wood?

7th Grade

Brandy Butcher

What is a physical change?

Change that affects one or more physical properties of a substance

A new substance is not formed

The substance keeps its identity (name)

Examples of Physical ChangeAny state change

◦Melting◦Freezing◦Evaporating

DissolvingCuttingBending

Examples of Physical Changes in NatureWater Cycle

Erosion

Can you think of any examples?

What is a chemical change?One or more substances are

changed into a new substance

New and different properties

New identity (name)

Examples of a Chemical Change

Cooking Burning

Rusting

Examples of Chemical Changes in NatureCarbon Cycle

Nitrogen Cycle

Chemical Weathering

Can you think of any examples?

What are the signs a chemical change is happening?Change in colorChange in odorProduction of heatProduction of fizzing, foam,

bubblesProduction of soundProduction of light

What signs do this changes demonstrate?

Light/Sound/

Heat

Light/Sound/

Heat

Change in odor and color

Change in color

Change in odor and color

Physical or Chemical Change?

Frying an egg?

Physical or Chemical

Incorrect. Try again!

Correct!

Try the next one!

Physical or Chemical Change?

Souring Milk?

Physical or Chemical

Incorrect. Try again!

Correct!

Try the next one!

Physical or Chemical Change?

Shredding paper?

Physical or Chemical

Incorrect. Try again!

Correct!

CreditsAll pictures used were free and

retrieved from www.morguefile.com.