Chemistry is The study of Matter and the changes it undergoes.
So what is matter?
Matter is anything that has mass and takes up space!
So what is matter?
The bison, the grass, and the air the bison breathes are all matter.
So what isn't matter?
Examples of things that aren't matter:
Love
Heat
Gravity
Happiness
Changes!
So what types of changes does matter undergo?
There are two broad ways chemists categorize changes:
Physical Changes
and
Chemical Changes
Physical changes
Physical changes are changes in which the composition doesn't change.
It's the same substance before and after!
Physical changes
Processes such as melting (and freezing, boiling, condensing) are considered physical changes.
It's H2O before and after.
Physical changes
Creating a mixture of two different substances also counts as a physical change.
When food colors are added to water, the composition of the food color and water don't change.
Chemical changes
In a chemical change, the composition of the materials changes from start to finish.
It started as wood. After burning, it's not wood!