September 27 2010 - Matter and Physical/Chemical Change

Today, we went over a common topic in science: matter. Matter is any object that takes up space and has a mass.

Matter is split into two categories: pure substances and mixtures.


Pure substances have only one set of properties, and only one kind of particle. Pure substances are split into elements, which are the simplest form and are made out of atoms (metal, non-metal and metalloid), and compounds, which are chemically compounded, made out of elements, and have small particles within them called molecules, which can be ionic or covalent.

Mixtures are the complete opposite, having more than one set of properties. Mixtures are grouped into homogeneous, being uniform throughout and only having one component, and heterogeneous, being non-uniform and having more than one component.

We also reviewed physical and chemical change, mainly looking at their differences.



Physical change is reversible, while chemical change isn't. It doesn't add any new substances into the product, unlike chemical change. Physical change also leaves the chemical composition the same as it was before the change.