States of Matter, Lesson 2 Changes in State October 28, 2011

Energy Kinetic energy: energy due to motion Faster = higher kinetic energy List the states of water in order from lowest kinetic energy to highest ______, ______, ______ Temperature: measure of average kinetic energy How do changes in temperature relate to changes in kinetic energy and vice versa?

Energy, cont. Potential energy: stored energy due to interactions between particles (ex. gravity) Increases when particles are further apart Decreases when particles are closer together

Energy, cont. Thermal energy: total potential and kinetic energy of an object Matter changes state by adding or removing thermal energy + thermal energy  inc. kinetic (particles move faster) and inc. potential (particles further apart) - thermal energy  ___ kinetic (particles move ______) and ____ potential (particles _______)

Comprehension check Describe the relationship between kinetic energy, potential energy and thermal energy. A: kinetic energy + potential energy = thermal energy

Changes in state (6 of them) Melting Solid to liquid Thermal energy added Melting point = temp at which solid turns to liquid

Freezing Liquid to solid Thermal energy removed Freezing point: temp at which liquid turns solid

Vaporization Liquid to gas Thermal energy added Boiling: vaporization in a liquid Boiling point: temp at which liquid turns to gas Evaporation: vaporization at the surface of a liquid

Condensation Gas to liquid Thermal energy removed

Sublimation Solid directly to gas Thermal energy added Ex. dry ice (solid carbon dioxide)

Deposition Gas directly to solid Thermal energy removed Ex. frost

Comprehension check Distinguish between changes in state that require the addition of thermal energy from those that require the removal of thermal energy.

EXIT PASS Differentiate between sublimation and deposition in terms of thermal energy.