2.THE DIFFERENT STATES OF MATTER. Experiments about the properties of solids, liquids and gases (from BBC: KS2-Bitesize): Gases, solids and liquids. A short quiz about this topic. Changing state. A short quiz about this topic. Solids and liquids. A short quiz about this topic. Visita Iniciación interactiva a la materia y selecciona estados de la materia. Look at the presentation. Simulations: particle model 1 (English) and  2 (Spanish). Interesting animations from skoool: Propeties of solids, liquids and gases. The particle theory. Change of state: water. Melting and boiling point. Video about thermal expansion of solids (1') Vídeo sobre dilatación de una bola de acero (40").