What to do… Write in your agenda: Homework: Study Guide due Monday! Open your physical science notes to page 29. Answer the following questions in the Think About It… How does ice become water? How does water become water vapor? What is happening to the particles?

Changes in State Chapter 8, Section 3 Standard: 9.6 – Compare the particle arrangement and type of particle motion associated with states of matter

Changes In State Occur as a result of the addition (endothermic) or removal (exothermic) of HEAT ENERGY!

Freezing Exothermic! From a liquid to a solid. Occurs when liquid reaches its freezing point. Freezing is a LOSS of heat energy. Exothermic!

Melting Endothermic! From solid to a liquid. When temperatures rise above the freezing point of a substance. Melting is a GAIN of heat energy. Endothermic!

The Freezing point of a substance is = to that substances melting point. EX. Water freezes and melts at 00 C

Evaporation Endothermic! From the liquid to gas. A GAIN of heat energy Boiling : the change of a liquid to a vapor, or gas. Called its boiling point.

Effects of Pressure on Boiling Point Atmospheric pressure varies depending on where you are in relation to sea level. It is lower at higher elevations & higher at lower elevations - Here water boils at 100°C. - In Denver, water boils at about 95°C.

Condensation From a gas to liquid. A LOSS of heat energy. Exothermic!

Real life connection – water cycle

Sublimation Endothermic! The changing of a solid DIRECTLY into a gas without passing through a liquid state. A GAIN of heat energy. Endothermic!

DO! Answer the following questions based on the previous lesson: Change in state of matter is what kind of change? Changing states of matter is caused by what? When you add or remove heat what are you adding or removing? True or False: When you add or remove energy it affects the movement of the molecules and causes a change in state of matter. Changing from a liquid to a gas is called what? Changing from a gas to a liquid is called what? Physical change Adding/removing heat Energy! evaporation condensation

DO! Answer the following questions based on the previous lesson: Changing from a solid to a liquid is called what? Changing from a liquid to a solid is called what? The temperature at which a liquid turns to a solid is called what? The temperature at which a solid turns to a liquid is called what? True or False: The freezing and melting points for a substance are the same. The temperature at which a liquid turns to a gas is called what? melting freezing Freezing point Melting point Boiling point

Keys to Understanding Write at least 3 sentences Summarize the notes in your OWN WORDS Explain the main ideas from the lesson