Reminders  States of Matter solids: fixed volume, rigid, definite shape ○ examples? liquids: flowing matter, definite volume, indefinite shape ○ examples? gases: flowing, compressible, indefinite shape ○ examples?

Kinetic Theory of Matter  submicroscopic particles of all mater are in constant, random motion  energy of moving objects is called kinetic energy  derived from Brownian motion (Robert Brown): constant, random motion of tiny chunks of matter

Kinetic Model of Gases  gas moves like an air-hockey puck; straight until hits the wall of the container or other particle, however unlike the puck, doesn’t lose kinetic energy with striking; rebounds w/o losing speed in a new direction = elastic collisions  ideal gas = elastic collisions  pressure = force acting on a unit area of a surface ex. outward pressure of air inside a balloon = force to keep it expanded Earth’s atmosphere = atmospheric pressure

Kinetic Model of Liquids  particles of liquids are closer together so don’t move as straight or smooth  similar to marbles (constant V, not shape) spread evenly to fill container if swirled, marbles flow if tipped, flow onto the table

Kinetic Model of Solids  strong forces between particle -> rigid structure  particles cannot move past each other but are in constant motion  fixed position in a 3D arrangement = crystal lattice

Changes in State  Evaporation What makes something evaporate faster?  Condensation  Sublimation