How are these three items alike? How are these three items different?

1. How are these three items alike? How are these three items different?

2. Phase ChangesI can define melting, freezing, boiling, condensation, and evaporation.I can explain the relationship between heat and matter.I can interpret information in a chart to distinguish one phase from another.

3. Melting The state of a substances depends on both its temperature and the amount of attraction between its particles. • The temperature at which a substance changes from a solid to a liquid is called the melting point. Any additional heat added to the material will not raise the temperature until all of the material is melted. • For example: If you heat some ice, its temperature will rise until it reaches 0° C (32° F). Then the ice will stay at that temperature until all the ice is melted. The heat energy is used to melt the ice and not to raise the temperature. After the ice is melted, the temperature of the water will continue to rise as more heat is applied. • Solid to a Liquid. • Solids have slow moving particles and when they gain heat they move faster and farther apart forming a liquid.

4. Freezing • Likewise, when particles/atoms in a substance lose energy, they move more slowly. If the substance cools enough, the particles/atoms slow down to the point where the liquid becomes a solid. • Then the temperature at which a liquid changes to a solid is called its freezing point. Once the liquid reaches the freezing point, the temperature will remain at that point until all of the liquid is solidified. Then the temperature of the solid can continue to decrease. • Liquid to a Solid. • Particles in a liquid have enough energy to spread far enough apart to move by one another and when energy/heat is taken away the particles move closer together, packing tightly into a solid form.

5. Boiling • If a liquid is heated enough, ALL the particles in the liquid will eventually have enough energy to break free at the surface. The temperature at which this occurs is called boiling point. • For example, the temperature of a pot of water will increase until it reaches 100° C (212° F). It will stay there until all the water is boiled away. • Liquid to a gas. • Particles in a liquid have enough energy to spread far enough apart to move by one another and when energy/heat is added the particles move faster and faster until they can break away.

6. Evaporation • Recall that temperature is the AVERAGE motion of particles and not all particles move at the same rate. • Even at room temperature, a few of the particles in a glass of water are moving fast enough to break free at the surface to become a gas. • But remember, ONLY a few, not all.

7. Condensation • Water vapor, a gas, is ALWAYS present in the air. • When the faster moving particles in the air collide with the slower moving particles on a cool surface, the gas particles lose energy. • When they are close enough, they collect back together into their liquid form. This is called condensation. • Gas to a liquid

8. Not All Matter Is Created Equal

9. Demonstration • What state of matter is the object in my hand? • What will happen if I add heat? • Let’s find out. • What will happen if I subtract heat? • What if I add more heat? • What if I subtract heat?

10. Your Turn! • You will be given a chart. Fill it out to show you can study the conditions the matter is undergoing and specify the phase change related to those conditions.