ATOC 1070 Lab 3Moisture in the AtmosphereSarah RoseGroup members: Zach H., Kitty D., Steven G.Section 8Question 1a. The water vapor capacity is 25 grams per k of air, and the actual amount of water vapor is 5 grams per kilogram. To find the relative humidity we use the formula RH = (Actual vapor pressure / saturation vapor) x 100 pressure so:RH = (5/25)x100 = 0.2%b. The mixing ratio is 10 grams per kg of air, and the saturation-mixingratio at 25 deg C is 20 grams per kg. To find the relative humidity we use the formula: RH = (mixing ratio/saturation mixing ratio) x 100 so, (10/20) x 100 = 50%c. The mixing ratio is 10 grams per kg of air, and the saturation vapor mixing ratio at 5 deg C is 10 grams per kg. To find the relative humidity we use the formula: RH = (mixing ratio/saturation mixing ratio) x 100 so, (10/10) x 100 = 100%The relative humidity in “c” is higher then the calculated RH in “b” because the temperature in “b” is greater. The greater the temperature the bigger the capacity there is in the atmosphere for water vapor. So even though both “b” and “c” have the same amount of water (10 grams per kg of air) the capacity in “c” is much greater it would take more vapor to make it saturated than in “b” because in “b” the temperature is lower. Two ways to change relative humidity would be to either raise or lower the air temperature. When you raise the temperature and keep the water amount the same RH goes down, when you lower the temperature and keep the water amount constant the RH goes up. Thesecond way to change the relative humidity would be to change the actual amount of water in the air. If you stay at a constant temperatureand add more water into the air then the RH goes up. Question 2Warm air can contain more moisture because the higher the temperature of the atmosphere the more energy there is. The more energy in the atmosphere there is more energy to evaporate water. So higher temps allow for more evaporation. You can have an atmosphere composed of 78% N, 21% O and 1% othergases because that is what a dry atmosphere looks like. When you addthe 4% that is water vapor the other 94% of the atmosphere is composed proportionally of 78% N, 21% O and 1% other gases. Location Dry Bulb deg CWet Bulb deg CDry – Wet (deg C)Dew Point deg CSat. Vapor PressurembActual Vapor Pressuremb% RHClassroom20 11 9 11 23.26 13.04 56%Outdoors 12 8 4 8 13.94 10.67 77%ATOC Skywatch12.17 X X -7.33 13.94 3.65 25%Question 3Air inside the classroom had more moisture. Actual vapor pressure is an absolute measure that tells you how much moisture is in the air. The data collected inside the lab says the actual vapor pressure is 13.04, which is greater, then the measured 10.67 from outdoors. The higher relative humidity was measured outdoors. The actual vapor pressure indoors is higher than the actual vapor pressure outdoors but the saturation vapor pressures are different resulting in different relative humidities. Question 4If we took another psychrometer reading a few minutes later and recorded our wet bulb temperature 1 deg C lower but the dry bulb stayed the same the Relative humidity temperature would be higher because the temperature has gone down but the same amount of moisture remains in the air there for the atmosphere is more saturated.If the temperature had gone up the RH would have decreased. The dewpoint would be lower because the wet bulb temperature dropped one degree meaning it is one degree closer to condensation then it was before. Dew point had a greater standard deviation the data had a far bigger more scattered range then the class temperature readings. The range of class dew point data ranged from -3 to 8 where temperature only ranged from 11 to 14 deg C. The standard deviation of dew point was 4.8 compared to temperature’s 1. The large range of values is likely due to errors caused by how different groups performed the experiment. Some groups might not have spun the psychrometer enough results in a higher dew point than actual.Summary and ConclusionIn this lab we learned the relevance of relative humidity and how to find it from actual humidity in part one of this lab. In part two of this lab we used an instrument called the psychrometer to find the temperature, dew point, saturation vapor pressure, actual vapor pressure and relative humidity of both the classroom and outdoors. In this lab we found that out of our measured data that the classroom hadlow RH (56%) then the outdoor reading of RH at (77%). The trouble with these findings are that the outdoor reading should have had similar results to the ATOC Skywatch lab since they are in proximity close to each other, but oddly enough the data collected outdoors was very off from the Skylab data. This might be due to improper twirling ofthe psychrometer or maybe damaged thermometers. We also concluded that the classroom had more moisture then the measured outdoor (which was consistent with the Skylab data) actual vapor pressure. Clearly there are points of error when we compare the outdoor data we collected in lab and the Skylab information. These sources of error (improper technique used with psychrometer and faulty thermometer) effect the outcome radically. With poor measurements it’s hard to definitively answer questions like which place is more moist or which location has higher relative humidity when the numbers are reliable. The first part of the lab helped me understand relative humidity and the difference between RH and actual humidity. I’m originally from Houston and humidity is part ofeveryday life there. Understanding the relationship between RH, temperature and water vapor is key to understanding why some places can have high RH but low actual humidity. If you were to get into a swimming pool when it was 90 deg F with 5kts winds and exit when it has dropped 35 deg F to 60 deg F with winds at 15 kts it would feel much colder because not only had the temperature dropped but the wind chill has