Learning area 5.0 Chapter HEAT KSSM FORM 2

Science kssm form 2

1. LEARNING AREA 5.0: Heat By: Cikgu Eni SMKKB

2. Sources Of Heat Electrical appliances Burning of fuel Sun (primary source of heat) Rubbing two hands together(Friction)

3. Content Standard: 5.1: Temperature and heat 5.2: Heat flow and thermal equilibrium

4. Learning Standard: By the end of this lesson, you should be able to: make comparison between heat and temperature explain how heat flows from a hot region to cold region. explain and communicate about heat flow in natural phenomena communicate about heat conductors and heat insulators and their uses in daily life

5. 5.1 Relationship between Temperature and Heat Heat – a form of energy flows from a hotter to a colder region

6. 5.1 Relationship between Temperature and Heat Temperature Measure of the degree of hotness or coldness of an object Measured by: thermometer

7. Same Temperature but Different Heat content A B

8. Same Heat content but Different temperature A B

9. HEAT TEMPERATURE form of energy degree of hotness and coldness of an object unit : joule (J) unit : o C / kelvin (K) depend on type of material quantity of material temperature depend on movement of particle

10. 5.2 HEAT FLOWS AND THERMAL EQUILIBRIUM Heat Flow -from hot object to cold object

11. T hot T hot T hot T hot T cold Ice cream left at room temperature absorbs heat and melts SOLID LIQUID Absorb heat

12. T cold T cold T cold T cold T hot Hot coffee left at room temperature releases heat and become cool

13. HEAT FLOWS IN THREE DIFFERENT WAYS By conduction through solids By convection through liquids or gases By radiation through empty space

14. 1. Conduction Heat transferred from particles to particles in solid from the hot end to the cold end Heat transfer

15. Examples of heat flow through conduction

16. ACTIVITY 5.1 To show heat is transferred by conduction

17. ACTIVITY 5.1

18. 2. Convection Transferred by the movement of liquid/gas

19. The hot liquid/gas becomes less dense than the cooler liquid/gas around it and rises As the warm liquid/air rises, cooler liquid/air rushes in to take its place This circulating stream known as convection current

20. CONVECTION IN AIR

21. 3. Radiation Transferring heat without any medium (vacuum) Rate: depend on types of surface, temperature and total surface area Example: Heat from sun transferred to Earth

22. HEAT FLOW IN NATURAL PHENOMENA Sea breeze Land breeze

23. 1. Sea breeze Blows during day From sea to land During the day, land becomes hot faster than sea Air above land becomes less dense and goes up Cool air from sea moves in to take its place

24. 2. Land breeze Blows during night From land to sea At night, land becomes cooler faster than sea Air above sea is heater than air above land Air above sea becomes less dense and goes up Cool air from land moves in to take its place

25. HEAT CONDUCTORS AND HEAT INSULATORS

26. Which temperature will drop faster? A B

27. EXPERIMENT 5.1 To study the uses of different materials as heat insulators What is your inference?

28. THERMAL EQUILIBRIUM

29. Content Standard: 5.3: Principle of expansion and contraction of matter 5.2: Relationship between the types of surface of objects to heat absorption & emission. 

30. Learning Standard: By the end of this lesson, you should be able to: Explain how heat can cause the expansion and contraction in solid, liquid and gas. Explain the uses of expansion and contraction of matter in daily life Demonstrate how dark, dull objects , radiate heat better than white shiny objects. Conceptualise and design the heat concept in daily life.

31. 5.3 PRINCIPLE OF EXPANSION & CONTRACTION OF MATTER in solid Gauge and metal bar When heated particles vibrate faster and move further apart from one another Volume of solid increase because solid expands

32. 5.3 PRINCIPLE OF EXPANSION & CONTRACTION OF MATTER in solid Gauge and metal bar When cooled particles vibrate slower and move closer to one another Volume of solid decrease because solid contracts

33. 5.3 PRINCIPLE OF EXPANSION & CONTRACTION OF MATTER in liquid When heated particles move faster and randomly Volume of liquid increase because liquid expands

34. 5.3 PRINCIPLE OF EXPANSION & CONTRACTION OF MATTER in liquid When cooled particles move slower and closer Volume of liquid decrease because liquid contracts

35. 5.3 PRINCIPLE OF EXPANSION & CONTRACTION OF MATTER in gas When heated particles move faster and randomly Volume of gas increase because gas expands

36. 5.3 PRINCIPLE OF EXPANSION & CONTRACTION OF MATTER in gas When cooled particles move slower and closer Volume of liquid decrease because liquid contracts

37. THE USES OF EXPANSION AND CONTRACTION OF MATTER IN DAILY LIFE 1. THERMOMETER Mercury in thermometer can expand and contract

38. THE USES OF EXPANSION AND CONTRACTION OF MATTER IN DAILY LIFE 2. RAILWAY TRACKS Small gaps between their rails to enable them to expand in hot weather

39. Without gaps, the tracks will buckle and overlap

40. THE USES OF EXPANSION AND CONTRACTION OF MATTER IN DAILY LIFE Built with rollers and a gap on one end 3. STEEL BRIDGES

41. THE USES OF EXPANSION AND CONTRACTION OF MATTER IN DAILY LIFE Used in devices that depend on temperature regulation. Eg : Iron and fire alarm system 4. BIMETALLIC STRIP Copper Iron

42. Which one copper? Which one iron?

43. FIRE ALARM SYSTEM

44. 5.4 RELATIONSHIP BETWEEN TYPES OF SURFACE OF OBJECT AND HEAT ABSORPTION AND EMISSION Dark and Dull White and shiny Which one you will choose?

45. Why fuel tanks are painted in bright colours ?

46. Bright colour  bad heat absorber. So, evaporation of fuel reduced

47. heat heat heat heat Evaporation INCREASED

48. heat heat heat heat Evaporation DECREASED heat heat heat heat

49. Black and dull White and shiny Good heat absorber Good heat radiator Good heat reflector THEORITICALLY,

50. Prove that: Dark object absorbs heat better than white objects

51. Prove that: Dark object radiates heat better than white objects

52. Hot water Dark and dull surface White and shiny surface

53. Black and dull White and shiny Good heat absorber Good heat radiator Good heat reflector SO, PROVE THAT,

54. WHICH IS THE BEST HOME PAINT COLOUR?

55. WHICH CLOTHING MAKE YOU HOTTER?