The document discusses the four states of matter: solid, liquid, gas, and plasma. It describes the key properties of each state, including how the particles are arranged and how they move. Solids have tightly packed particles that vibrate in a fixed position. Liquids also have tightly packed particles that can slide past one another. Gas particles are far apart and move freely. Plasma has electrically charged particles with no definite shape or volume. The document also provides links to online resources about phase changes and states of matter.