Theme 2.

Changes in the matter!

Changes are classified as phisical or chemical changes.

Physical changes: are when a substance changes form but not chemical composition. these changes are usually reversible for example: water to ice.

Chemical changes: are when a substance changes chemical composition by creating new substances, these changes are usually imposible to change for example: burning paper.

Chemical and Physical changes are important in classifying material.

Indicators of a chemical change:
- heat is produced or absorbed
- the starting material is used up
- there is a change in color
- a material with new properties forms
- gass bubbles form in a liquid
- a precipitate forms in a liquid
- the change is difficult to reverse

Julie and Ashlea :)