States of Matter Matter commonly occurs in one of three “states” Solid Liquid Gas There are two others Plasma (very hot) Bose-Einstein condensate (very cold)

Solids Solids have A definite shape A definite volume The shape of a solid is not dependent on a “container” The volume of a solid does not change

Liquids Liquids have Liquids take on the shape of their container A variable shape A definite volume Liquids take on the shape of their container The volume of a liquid does not change

Gases Gases have Gases take on the shape of their container A variable shape A variable volume Gases take on the shape of their container Gases expand their volume to completely fill their containers

The Kinetic Theory of Matter All particles of matter are in constant motion There are forces of attraction between particles The strength of the attraction decreases as the speed of the particles increases Fast-moving particles bounce around and collide Medium-moving particles touch but slide around Slow-moving particles vibrate in place The temperature of a material is directly related to the average speed of its particle motion

Kinetic Theory - visually

Phase Changes The processes by which matter changes from one state to another Melting/ freezing Vaporization/ condensation Sublimation/ deposition

Temperature in Phase Changes The temperature of a substance does not change during a phase change (even though thermal energy is being added or removed)

Energy in Phase Changes Energy (thermal) is either absorbed or released during a phase change Endothermic – absorbs energy (substance is heated) Exothermic – releases energy (substance is cooled)

Solid-Liquid-Solid Melting Freezing Solid to liquid Absorbs energy Liquid to solid Releases energy

Liquid-Gas-Liquid Vaporization Condensation Liquid to gas Absorbs energy Evaporation Below boiling point At surface of liquid Boiling At boiling point Within/throughout the liquid Condensation Gas to liquid Releases energy

Solid-Gas-Solid Sublimation Deposition Solid to gas Absorbs energy Gas to solid Releases energy

Putting It All Together

Transferring Thermal Energy Thermal energy can be transferred from one object to another object in three ways: Radiation Conduction Convection Thermal energy is ALWAYS transferred from the object that has more thermal energy to the object that has less thermal energy Thermal energy flows from hot things to cold things as long as there is a difference in temperature

Radiation Radiation is the transfer of thermal energy by electro-magnetic waves We commonly experience this with infrared and visible light

Conduction Conduction is the transfer of thermal energy by the direct interaction of atoms This requires that the objects be in physical contact with one another

Convection Convection is the transfer of thermal energy by the movement of a heated material This often results in circular movement patterns called convection cells