3. What is the name of the process by which water forms on the outside of the glass?

4. If NO water is forming on the outside of one glass, explain why that is or what would need to change in

order for you to see water form.

Exercise 7.2:

1. The data in Table 1 were recorded on July 18 in Fullerton, California. Notice that the hours are given in

military time (e.g., 0100 = 1:00 a.m. and 1300= 1:00 p.m.) and that temperatures are recorded in

degrees Fahrenheit.

Use the information in Table 1, to plot the air temperature and Relative Humidity experienced on July 18

(plot both on the same graph, using one color for temperature and one for Relative Humidity). Don't forget

to label your graph. You can either plot the data on the chart provided OR enter the data into the Excel

sheet provided. If you use the Excel sheet, please past a copy of the chart into your lab.

Time

Temperature (°F)

0000

0100

0200

0300

0400

0500

0600

0700

0800

0900

1000

1100

1200

1300

1400

1500

1600

1700

1800

1900

2000

2100

2200

2300

65

65

65

65

65

64

65

65

70

72

76

78

81

83

83

83

84

81

79

77

74

70

69

68

TABLE 1

Relative

Humidity

83

84

85

86

84

84

83

82

75

71

64

57

55

52

51

50

47

51

56

59

67

75

78

80

N/nLab Seven: Humidity

This lab is designed to help you understand the relationship between water vapor content, temperature

and humidity.

Objectives:

Calculate relative humidity

.

Find relative humidity using sling psychrometer

• Determine dew point temperature based on

water vapor content

Part 1: Relative Humidity and Dew Point Temperature

Relative Humidity:

Name

Mixing Ratio:

Saturation Mixing Ratio:

Relative Humidity (%):

Dew Point Temperature:

describes how close the air is to saturation. It is expressed as a ratio of water

vapor content (Mixing Ratio) to the total amount of water vapor the air mass can

hold (Saturation Mixing Ratio)

actual amount of water vapor present in a given parcel of air.

Expressed as grams of water vapor/kilogram of dry air (g/kg).

amount of water vapor (grams) a parcel of air can hold at a given

temperature. Expressed as grams of water vapor/kilogram of air (g/kg).

Mixing Ratio (Actual)/ Saturation Mixing Ratio (Capacity) x 100

the temperature to which a given parcel of air must cool, so that relative

humidity is 100%

Exercise 7.1:

At home experiment:

Step 1: Place a glass in the freezer until well chilled. Remove and fill with ice and water.

Step 2: Take a different glass and fill it with room temperature water.

Step 3: Wait 15-20 minutes. Take a picture of both glasses. Examine both glasses, then answer the following

questions.

1. Explain, in detail, why water is forming on the outside of one glass but not the other.

2. Give all steps that must have occurred in order to make water form on the outside of the glass.