DPT

1
DPT Relative Humidity Charts

• Handy Dandy Earth Science Reference Tables Page 12

2
The Dry Bulb

• Dont let it fool you. It is just a thermometer.
• It measures the air temperature.
• Duh!

20C
3
The Wet Bulb

• Has a little wet booty tied to the bottom.
• Gets cool when water evaporates.

12C
Wet Booty
4
A Dry Day

• A lot of moisture will evaporate.
• The wet bulb will be a lot cooler than the dry
  bulb.

20C
Difference between wet bulb dry bulb is 12 C.
5
A Humid Day

• A little bit of moisture will evaporate.
• The wet bulb will not be much cooler than the dry
  bulb.

20C
14C
Difference between wet bulb dry bulb is 6 C.
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Page 12 of your Handy Dandy Earth Science
Reference Tables

• Warning 1 Be sure to READ the correct chart
  DPT or RH
• Warning 2 Dew Point Temperature IS NOT
  Difference between wet bulb and dry bulb.
• Warning 3 The wet bulb temp IS NOT the DPT.

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Dry-bulb temperature is your air temperature.
20 C
8
14 C
9
4 C
10
Subtract (the difference) between the dry bulb
and wet bulb
11
20C
14C
20-146
12
18C
16C
18-162
13
Put it all together
20C
8C
20-812
Relative Humidity 11
14
14C
10C
14-104
Relative Humidity 60
15
The Dew Point Chart works the same way
14C
10C
14-104
Dew Point 6C
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Try These.
Dry Bulb Wet Bulb R Humidity DPT
26C 20 C
6 C 5 C
12 C 8 C
18 C 17 C
14 C 14 C
0 C -3 C
57
17 C
86
4 C
57
4 C
91
16 C
100
14 C
45
-9 C
17
More Difficult.
Dry Bulb Wet Bulb R Humidity DPT
21C 19C
11C 6 C
17 C 17C
2C -3 C
9C 6.5 C
70F 60 F
82
18 C
45.5
-.5 C
100
17 C
20
-17 C
69
3.5 C
15 C
52
11 C(50 F)
21 C
18
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The End