Notes for 3/13

1. Objectives
Describe humidity and relative humidity
Explain how clouds are formed
Identify the basic characteristics of different cloud groups

2. Question
How are clouds formed?

3. Humidity

4. Humidity
On warm summer days, what
does it feel like outside?

5. Humidity

6. Humidity
Concept: Warm air holds more
water vapor than cool air.

7. Humidity
Concept: Warm air holds more
water vapor than cool air.
Why?

8. Humidity
Concept: Warm air holds more
water vapor than cool air.
Why?
Fast moving air molecules leave
more space for water molecules

9. Humidity
Concept: Warm air holds more
water vapor than cool air.
Why?
Fast moving air molecules leave
more space for water molecules
Water molecules are moving fast
so they can’t stick together

10. Humidity

11. Humidity
Humidity: The amount of water
vapor in air

12. Humidity
Humidity: The amount of water
vapor in air
Relative humidity: The amount
of water vapor in air compared
to how much water vapor the air
can hold.

13. Cloud Formation

14. Cloud Formation
Think back to yesterday ...

15. Cloud Formation
Think back to yesterday ...
How does a cloud form?

16. Cloud Formation

17. Cloud Formation
We are going to add to that
picture

18. Cloud Formation
We are going to add to that
picture
Water molecules cannot just
slow down and stick to each
other

19. Cloud Formation
We are going to add to that
picture
Water molecules cannot just
slow down and stick to each
other
Must stick to something else
first.

20. Cloud Formation

21. Cloud Formation
Condensation Nuclei: Small
particles in the atmosphere that
water molecules can cling to

22. Cloud Formation
Condensation Nuclei: Small
particles in the atmosphere that
water molecules can cling to
May be salt, dust, or another
solid particle

23. Cloud Formation

24. Cloud Formation
Orographic Lifting

25. Cloud Formation
Orographic Lifting
Wind blowing along the
Earth’s surface runs into a
mountain

26. Cloud Formation
Orographic Lifting
Wind blowing along the
Earth’s surface runs into a
mountain
Air has nowhere to go but up

27. Cloud Formation
Orographic Lifting
Wind blowing along the
Earth’s surface runs into a
mountain
Air has nowhere to go but up
As the air rises it cools and
condenses

28. Cloud Formation

29. Cloud Formation
Air Mass collisions

30. Cloud Formation
Air Mass collisions
If a cold mass of air and a
warm mass of air collide, what
do you think happens?

31. Cloud Formation
Air Mass collisions
If a cold mass of air and a
warm mass of air collide, what
do you think happens?
The warm air is forced up

32. Cloud Formation
Air Mass collisions
If a cold mass of air and a
warm mass of air collide, what
do you think happens?
The warm air is forced up
It cools and forms a cloud

33. Cloud Formation

34. Cloud Formation
Sea Breeze

35. Cloud Formation
Sea Breeze
Cool air over the ocean moves
towards land

36. Cloud Formation
Sea Breeze
Cool air over the ocean moves
towards land
When the cool air reaches
land it warms and rises

37. Cloud Formation
Sea Breeze
Cool air over the ocean moves
towards land
When the cool air reaches
land it warms and rises
Rising air cools and
condenses

38. Cloud Formation
Sea Breeze
Cool air over the ocean moves
towards land
When the cool air reaches
land it warms and rises
Rising air cools and
condenses
Forms clouds

39. Cloud Formation

40. Cloud Formation
Stability: The ability of an air
mass to resist rising

41. Cloud Formation
Stability: The ability of an air
mass to resist rising
The warmer an air mass, the less
stable it is

42. Cloud Formation
Stability: The ability of an air
mass to resist rising
The warmer an air mass, the less
stable it is
The cooler an air mass the more
stable it is

43. Types of Clouds

44. Types of Clouds
Words

45. Types of Clouds
Words
Strato - Low (below 2000 m)

46. Types of Clouds
Words
Strato - Low (below 2000 m)
Alto - Middle (2000 m - 6000
m)

47. Types of Clouds
Words
Strato - Low (below 2000 m)
Alto - Middle (2000 m - 6000
m)
Cirro - High (Above 6000 m)

48. Types of Clouds

49. Types of Clouds
Words

50. Types of Clouds
Words
Cirrus - Hair (Stringy clouds)

51. Types of Clouds
Words
Cirrus - Hair (Stringy clouds)
Cumulus - Pile (Puffy clouds)

52. Types of Clouds
Words
Cirrus - Hair (Stringy clouds)
Cumulus - Pile (Puffy clouds)
Stratus - Layer (sheet of
clouds)

53. Types of Clouds
Words
Cirrus - Hair (Stringy clouds)
Cumulus - Pile (Puffy clouds)
Stratus - Layer (sheet of
clouds)
Nimbus - Cloud (Low, dark,
rain clouds)

54. Types of Clouds

55. Types of Clouds
Keep your words out and answer
the following questions

56. Types of Clouds
Keep your words out and answer
the following questions
What is the height and shape of
a stratocumulus cloud?

57. Types of Clouds
Keep your words out and answer
the following questions
What is the height and shape of
a stratocumulus cloud?
A. Middle and Flat

58. Types of Clouds
Keep your words out and answer
the following questions
What is the height and shape of
a stratocumulus cloud?
A. Middle and Flat
B. Middle and Puffy

59. Types of Clouds
Keep your words out and answer
the following questions
What is the height and shape of
a stratocumulus cloud?
A. Middle and Flat
B. Middle and Puffy
C. Low and Puffy

60. Types of Clouds
Keep your words out and answer
the following questions
What is the height and shape of
a stratocumulus cloud?
A. Middle and Flat
B. Middle and Puffy
C. Low and Puffy
D. Low and Flat

61. Types of Clouds

62. Types of Clouds

63. Types of Clouds
What is the height and shape of
a stratocumulus cloud?

64. Types of Clouds
What is the height and shape of
a stratocumulus cloud?
C. Low and Puffy

65. Types of Clouds

66. Types of Clouds
What is the height and shape of
a cirrus cloud?

67. Types of Clouds
What is the height and shape of
a cirrus cloud?
A. low and flat

68. Types of Clouds
What is the height and shape of
a cirrus cloud?
A. low and flat
B. high and stringy

69. Types of Clouds
What is the height and shape of
a cirrus cloud?
A. low and flat
B. high and stringy
C. Middle and puffy

70. Types of Clouds

71. Types of Clouds
What is the height and shape of
a cirrus cloud?

72. Types of Clouds
What is the height and shape of
a cirrus cloud?
B. high and stringy

73. Types of Clouds

74. Types of Clouds
What is the height and shape of
an altostratus cloud?

75. Types of Clouds
What is the height and shape of
an altostratus cloud?
A. middle and flat

76. Types of Clouds
What is the height and shape of
an altostratus cloud?
A. middle and flat
B. high and stringy

77. Types of Clouds
What is the height and shape of
an altostratus cloud?
A. middle and flat
B. high and stringy
C. low and puffy

78. Types of Clouds

79. Types of Clouds
What is the height and shape of
an altostratus cloud?

80. Types of Clouds
What is the height and shape of
an altostratus cloud?
A. middle and flat

81. WHAT IS IT?
Nimbostratus

82. WHAT IS IT?
Stratocumulus

83. WHAT IS IT?
Cumulus

84. WHAT IS IT?
Altocumulus

85. WHAT IS IT?
Cirrocumulus

86. WHAT IS IT?
Cirrus

87. WHAT IS IT?
Cirrostratus

88. WHAT IS IT?
Cumulonimbus