1. Why Phase Change Occurs
Heating and Cooling Curve explained

2. Temperature
Is a measure of the average kinetic energy of the molecules within an object.
Energy of motion

3. Thermal Energy Aka HEAT ENERGY…
Every substance contains energy from the movement of its particles.
EX. Increase temperature = Greater Thermal/Heat Energy

4. Movement of Molecules Increase Temperature: Molecules will move FASTER
Decrease Temperature:
Molecules will move SLOWER

5. Heating/Cooling Curve
Vaporization

6. Heat or energy absorbed by the ice is used to raise the temperature of the ice.

7. SOLID: The molecules that make up ice are very close and held together by a strong force called a bond.
BOND A
FORCE between molecules is STRONGEST in the SOLID state of matter.

8. Heat or energy absorbed by the ice is used to break the bonds between the molecules – so that the ice begins to melt. NO TEMPERATURE CHANGE!!! B

9. Heat energy is used to break the bonds in the solid ice
Heat energy is used to break the bonds in the solid ice. Ice starts to become water.
BOND B

10. BOND B

11. BOND B

12. BOND B

13. BOND B

14. BOND B

15. BOND B

16. Once the bonds have been broken and all the ice becomes water…then heat energy is used to raise the temperature of the water. C

17. LIQUID: The molecules that make up water are more separated than in a solid.
They are still held together bonds, but they are less of them. Therefore, they are not as strong. C
Puddle of water

18. LIQUID: The molecules that make up water are more separated than in a solid.
They are still held together bonds, but they are less of them. Therefore, they are not as strong. C
Puddle of water

19. LIQUID: The molecules that make up water are more separated than in a solid.
They are still held together bonds, but they are less of them. Therefore, they are not as strong. C
Puddle of water

20. Heat or energy absorbed by the water is used to break the bonds between the molecules – so that the water begins to become a gas.
NO TEMPERATURE CHANGE!!! D

21. Heat energy is use to break the bonds in the water
Heat energy is use to break the bonds in the water. Water starts to become steam and then water vapor. D
Puddle of water

22. Heat energy is use to break the bonds in the water
Heat energy is use to break the bonds in the water. Water starts to become steam and then water vapor. D
Puddle of water

23. Heat energy is use to break the bonds in the water
Heat energy is use to break the bonds in the water. Water starts to become steam and then water vapor. D
Puddle of water

24. Heat energy is use to break the bonds in the water
Heat energy is use to break the bonds in the water. Water starts to become steam and then water vapor. D
Puddle of water

25. Heat energy is use to break the bonds in the water
Heat energy is use to break the bonds in the water. Water starts to become steam and then water vapor. D
Puddle of water

26. Once the bonds have been broken, the water becomes water vapor
Once the bonds have been broken, the water becomes water vapor! Heat energy is used to raise temperature. E

27. Water vapor E