Where we are in the standards…

1. Where we are in the standards… • 9.1 • Energy Transfer and Transformations – What is the role of energy in our world? • D 1.Describe the effects of adding energy to matter in terms of the motion of atoms and molecules, and the resulting phase changes.

2. What is matter? • Matter: a physical substance that occupies space and possesses mass. • Distinct from mind, spirit and energy. • Energy: power derived from the utilization of physical or chemical resources Ex: light and heat.

11. Essential Question • What are the effects of energy on a micro and macro level?

12. Heat

13. Kinetic vs. Potential Energy • Kinetic Energy- energy a moving object has because of its motion. • Dependant on the object’s mass and its speed. • Potential Energy- stored energy an object has due to its position.

14. Temperature • Matter is made of particles (atoms and molecules). • These particles are constantly in motion. • The speed that these particles are moving determines the temperature of an object. • Temperature- a measure of the average kinetic energy of the particles in an object.

15. Temperature • Three Scales: Fahrenheit (˚F) Celsius (˚C) Kelvin (K) • Conversion Formulas: ˚C = (˚F - 32) x 5/9 ˚F = (C x 1.8) + 32

16. Heat • Heat- the total kinetic energy of the particles that make up a substance. Units- joules or calories (cal) • When you add heat to an object, you are adding energy to that object. • The increase in kinetic energy causes the object to expand. • Heat flows from warmer to cooler materials.

17. Heat • The rise in temperature is dependant on the amount of heat that is added to an object. • Make a prediction: What would happen if the same amount of heat is added to a small beaker of water and a large beaker of water?

18. Specific Heat • Specific Heat- the amount of heat that is needed to raise the temperature of 1kg of a material by 1˚C. • This measurement determines how things conduct heat. • Example- Plastic has a higher specific heat than metal which is why we use plastic spoons when we cook.

19. When heat is added to a substance its particles vibrate faster; over a greater distance; causing the material to expand.

22. Thermal Energy • Thermal Energy- the sum of the kinetic and potential energy of all of the particles in an object . • The kinetic energy is the movement of the particles that make up the object. • The potential energy is the energy stored in the bonds that are holding the particles together.

23. Summary • Heat – the total KE of a material. • Temperature – the average KE of a material. • Thermal Energy – the KE and PE of a material. • Specific Heat - the amount of heat that is needed to raise the temperature of 1kg of a material by 1˚C. • True or False: For any two objects, the one with the higher temperature always has more thermal energy.

24. Review Questions • Describe how the thermal energy of an object changes when the object’s temperature changes. • When heat flows between two objects, does the temperature increase of one object equal the temperature decrease of the other?

25. Phase Changes • There are four main states of matter: • Solid • Liquid • Gas • Plasma

26. Solid • Solid- a substance with a definite volume and shape. • The particles are vibrating in place, held in place by attractions between the particles. • Chemical and physical properties of a substance are determined by the geometric pattern of the molecules.

27. Liquid • Liquid- A substance with a definite volume, but no definite shape. • The particles in a liquid can flow freely with in the substance, but attractions between the particles keep them from escaping. • The liquid will take the shape of its container.

28. Gas • Gas- a substance without a definite shape or volume. • The particles in a gas have very little attraction for each other and so they can move about freely taking the size and shape of their container.

29. Plasma • Plasma- a high energy state of matter in which atoms lose their electrons and exist as electron free nuclei in a sea of electrons. • This requires temperatures greater than 1 million degrees Celsius. • Natural Plasmas exist as stars and can be created for a brief time by very powerful lightning bolts (1million + volts)

30. Phase Changes • Heating: Adding heat to a substance causes its particles to move faster. If there is enough energy they will break the attractions holding them in that state and move up to the next state. • Cooling: Removing heat from a substance causes its particles to slow down and allows the attractions to begin to affect the particles drawing them together into a lower state.

31. Phase Changes • During a phase change the temperature remains constant, because the energy changes are associated with making/breaking attractions, not with particle movements.

32. Melting Point- the temperature at which a solid becomes a liquid. • Freezing Point- liquid becomes a solid. • Boiling Point- liquid becomes a gas. • Triple Point- The temperature and pressure at which the solid, liquid, and vapor phases of a pure substance can coexist in equilibrium

34. Heating Curve

35. Melting- a solid becomes a liquid. Freezing- a liquid becomes a solid.

36. Vaporization- a liquid becomes a gas. • Condensation- a gas becomes a liquid.

37. Some materials can undergo a change in state between the solid state and gaseous state without becoming a liquid. • Sublimation- a solid becomes a gas. • Deposition- a gas becomes a solid.

38. Analysis Questions • Was heat being added to the system during the time that the temperature remained relatively constant? How was the heat being used during these temperature plateaus? 

39. During this experiment, heat was being added to the system, but at times the temperature remained relatively constant. During this time the energy being added to the system in the form of heat was being used to break the bonds or attractions between the molecules causing a phase change.

40. Analysis Questions • Was heat being added to the system during the time the temperature was rising? How was the heat being used at this time?

41. During this experiment, heat was being added to the system and the temperature of the water was increasing. The energy being added to the system in the form of heat was increasing the kinetic energy, the motion of the particles, making up the water.

42. Closure

43. Do Now September 16th, 2011 • Take out your homework: Analysis Q’s and Heating Curve/Phase Change Worksheet) • On a piece of paper fill in the following… • Your mood note. (I am… because…) • What is radiation? • Go to the board and fill in ONE of the answers to the homework in the one of the two diagrams provided.

44. Lesson Recap • What did we learn during our last class meeting?

46. What is happening to the thermal energy on a micro and macro level if the temperature of the water is not increasing during segments BC and DE?

48. In order for a liquid to change to a gas, heat is added to the substance causing the kinetic energy of that substance to increase, allowing the molecules to overcome the attractive forces holding them together. Describe how a gas changes to a liquid.