https://www.khanacademy.org/science/grade-6-science-tx/x6eddf2e1c524bf5a:properties-of-matter 2026-06-30T21:40:41.000025973Z Properties of matter Learn how scientists define matter, then explore the three states of matter—solids, liquids, and gases. Discover the relationship between kinetic energy and phase changes. Discuss how matter can be identified using physical properties, and learn how matter can be classified as pure substances or mixtures. Finally, explore how the physical property of density allows us to make predictions about how matter behaves. unit