Anything with mass that takes up space is matter. Examples would be: this computer, the air around you, and you!
Scientists classify matter into two groups: mixtures and pure substances.
Pure Substances
Have a constant composition—uniform throughout
Cannot be broken down into simpler substances by physical means
Are either elements (composed of one type of atom) or compounds (two or more types of atoms that are chemically bonded)
Mixtures
Can be separated by physical means (filtration, magnetism, boiling, by hand)
Are homogeneous if uniform throughout
Are heterogeneous if not uniform throughout
Check out this video describing how your breakfast foods are either heterogeneous or homogeneous mixtures.
Source: ScienceMan Digital Lesson - Mixtures - Homogeneous/Heterogeneous, ScienceMandotcom, YouTube
Click on the site below to read about elements, compounds and mixtures. Pay attention to the animation. Elements, Compounds & Mixtures
Click on this website to virtually separate some mixtures. Be sure to read the directions at the top of the screen. Answer the questions below when you finish. Mixtures
Click the radio button for the answer you think is correct. You will receive feedback to the right of each question.