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1. Heat is a measure of energy (J)

2. Heat is measured on an absolute scale

3. There is no such thing as cold energy, if something is cold it is because it doesn't have much heat energy

4. Temperature is a measure of hotness (degrees celcius)

5. The hotter something is in comparison to its surroundings, the quicker it will cool down

6. A thermogram indicates temperature

7. Heat energy always flows from hotter to cooler bodies

8. Specific Heat Capacity is the energy needed to raise the temperature of a 1kg block of material by 1 degrees celcius

9. A high specific heat capacity will mean the material takes a lot of energy to heat up, and has to lose a lot of energy to cool down

10. Specific Latent Heat is the energy needed to change the state of 1kg of a material

11. When a material changes state, the temperature does not increase as the energy is used to break intermolecular bonds rather than increasing the kinetic energy of the molecules

12. A high specific latent heat means it takes a lot of energy to change its state

13. The particles in a hot object have more kinetic energy than a cold object

14. Heat Is transferred by conduction by the particles vibrating and making those next to them vibrate

15. Conduction only occurs in solids as the particles cannot move around

16. Warm air is less dense and so rises

17. Convection is the movement of air from one place to another

18. Heat is transferred by radiation as a wave

19. Radiation can only occur in all states of matter and a vacuum as it doesn't need particles

20. Trapped air is a good insulator as the particles aren't close enough together for conduction to take place and the particles can't move so convection can't take place

21. A cavity wall is 2 layers of brick with a gap (cavity) inbetween

22. Some cavity walls have foam in the gap, this is called cavity wall insulaion

23. Electromagnetic waves travel in straight lines

24. The EM spectrum in order of wavelength is:

    • Gamma --> X-Ray --> UV --> Light --> Infrared -> Microwaves --> Radiowaves

25. If wavelength increases then frequency decreases

26. Reflection is when a wave changes direction by bouncing of an suraface

27. Refraction is when a wave changes direction by entering a different material

28. Refraction occurs because waves go at different speeds in different materials

29. Diffraction is when waves spread out after going through a gap/opening

30. Diffraction occurs the most when the gap is a similar size to the wavelength

31. Using light increases the speed of communication

32. Total internal reflection is when a wave stays inside a material by bouncing off the internal walls

    • Total internal reflection occurs when the angle of incidence is bigger than the critical angle for the materials
      • If the angle of incidence is too small the light will leave the material rather than staying inside

33. Lasers produce an intense, narrow beam of light of a single colour

34. The waves in a laser beam are coherent, which means they are all in phase

35. Lasers can be used in surgery and dental treatment, for cutting materials in industry, weapon guidance and in laser light shows

36. Morse code is a series of on and off signals, which means it is digital

37. The best emitters and absorbers are dull and black

38. The worst emitters and absorbers are shiny and white

39. Mobile phones use microwave signals

40. Properties of infrared radiation include: heats the surface of food and is reflected by shiny surfaces

41. Infrared is absorbed only by particles on the surface of the food increasing their energy

42. This energy is then transferred to the rest of the food by conduction and convection

43. Properties of microwave radiation include: they penetrate into food, are reflected by shiny metal surfaces, can cause burns when absorbed by body tissue and can pass through glass and plastics

44. Water and fat absorb microwaves

45. Microwaves are absorbed only by water and fat in the outer layers of the food increasing their KE

46. when microwaves transmit information there is some signal loss due to interference, the curvature of the earth, no diffraction around objects and adverse weather

47. The evidence of dangers from mobiles is not inclusive

48. Therefore it is not easy to decide on the siting of phone masts

49. As you increase the frequency of a microwave the energy increases

50. Analogue signals have a continuously variable value

51. Digital signals are either on or off

52. Everyday uses of infrared radiation include: remote controls and short distance data links

53. Infrared sensors detect body heat

54. The advantages of using digital signals include: that it is easier to remove noise and you can use multiplexing

55. Multiplexing is when you send one or more than one signal carrier wave

56. The advantages of using optical fibres include: multiplexing and lack of interference in the final signal

57. Wireless technology uses electromagnetic radiation

58. The advantages of wireless technology are: no external/direct connection to a telephone needed, portable and convenient, allows access when on the move

59. The advantages of DAB radios are: more stations available, less interference with other broadcasts

60. The disadvantages of DAB radios are: poorer quality compared to FM, not all areas covered

61. Radiation used for communication is refracted and reflected and this can be an advantage or disadvantage for good reception

62. Common uses of wireless technology include: TV and radio, mobile phones and laptop computers

63. Radio waves exhibit total internal reflection

64. Shock waves form earthquakes can be detected by seismometers and recorded on seismograph

65. Shockwaves from earthquakes can cause damage to buildings and at the Earth's surface and tsunamis

66. P waves are longitudinal

    • P waves travel through both solids and liquids
      • P waves travel faster than S waves

67. S waves are transverse

    • S waves only travel through solids

68. Exposure to UV radiation can cause: suntan, sunburn, skin cancer, cataracts and premature skin ageing

69. Sunscreens can reduce damage to skin

70. SPF stands for Sun protection factor

71. Darker skins have lower cancer risks as they absorb more ultraviolet radiation so less UV reaches the underlying issues

72. The ozone layer protects the Earth from ultraviolet radiation

    • Scientists were surprised to find the ozone hole
      • The ozone layer has been depleted by environmental pollution from CFCs