1. Cool air while keeping the actual mixing ratio constant until the saturation mixing ratio equals the actual mixing ratio.
2. Add water vapor to the air to increase the actual mixing ratio until it equals the saturation mixing ratio.
3. Mixing cool and warm, moist but unsaturated air to produce air with a temperature in-between and saturated air. This is a result of the fact that when the air temperature is changed, the saturation mixing ratio changes more rapidly than the temperature changes.  The conditions must be just right or it will not work.

#6 Energy must be extracted from the liquid water to form ice. In the atmosphere this energy is given off to the surrounding air.
#7 Relative humidity is defined as (actual mixing ratio)/(saturation mixing ratio) * 100 %.
#8 The energy that is being transported is the latent energy associated with the phase transformation of water.

1. In the case of evaporation > condensation the net transport of water molecules is from the liquid to the vapor phase. Each molecule that leaves the liquid water takes energy away from the surface. So the net transport of energy is away from the surface.
2. For evaporation rate = condensation rate, the net transport of molecules and energy is zero, since the # of molecules going from liquid to vapor is equal to the # going from vapor to liquid.
3. When the rate of evaporation < the rate of condensation, the net transport of molecules is toward the liquid water surface. So, the transport of energy is into the liquid since the water molecules must release energy to go from vapor to liquid. This released energy can go into increasing the temperature of the water.

#9 If the RH=50% and the dew point temperature (Td) is 0 C, then what is the air temperature? (Use the definition of RH and the chart on the handout concerning moisture.)   The definition of RH=W/Ws * 100 %, and knowledge of the dew point temperature (Td) can be used to calculate the air temperature. First, air temperature and Ws are related via the table on the handout. So, if we know the value of Ws, then we can use the table to get the air temperature. Ws can be obtained from the RH equation like so:
Start with
RH=W/Ws*100%
Next we need to know what is the value of W. The dew point temperature and the table can give us this. If Td=0C, then there would be 3.5 grams of water vapor per kilogram of dry air (W=3.5g/kg). Substituting this value of W and RH into the above equation we obtain,
50%=3.5g/kg/Ws*100%
If we solve this equation for Ws (multiply both sides by Ws and divide both sides by 50%) to get
Ws=3.5 g/kg/50% * 100% = 3.5 g/kg * 2 = 7 g/kg.
If we look on the chart we see that a saturation mixing ratio of 7 g/kg corresponds to an air temperature of 10 C. So, the answer would be 10 C.
#10. The temperature of the liquid water; the higher the temperature the greater the evaporation rate. The wind speed of air above the liquid water; the higher the wind speed, the greater the rate at which water that has been evaporated is advected (horizontal form of convection) away from the source of evaporation.
#11 The processes sublimation, evaporation and melting each require energy from the surrounding environment. The processes deposition, condensation and freezing each require energy from the surrounding environment.
#12 Remember the definition of RH in #7. Here, w=5.50 g/kg and Ws=27.69 g/kg, so RH=5.5/27.69*100% = 21%.
#13 Since the dew point temperature is never greater than the air temperature, then highest the dew point could be would be dependent upon the air temperature. Since the air temperature is generally greater in the summer, the dew point could also be higher then. In addition, the temperature of the surface, including bodies of water, is also higher during the summer, so the evaporate rate would be larger then also. So, you'd expect the concentration of water vapor in the air to be greater in the summer.
#14 What form of energy transport in the atmosphere is effected by the RH of the air? Somewhat of the trick question I guess. The RH will tell us in what direction is the net transport of water. (See question #8.)

1. Sensible heat: Though one could argue that as the RH changes then the latent heat transport changes, so the energy available for sensible heat transport also changes. However, I was looking for an answer somewhat like, "The temperature of the object and the difference with the surrounding environment determines the size the sensible heat transport. So, RH does not affect this form of energy transport.
2. Radiation: Water vapor can influence the transport of energy in the atmosphere via radiation in water vapor and absorb and emit radiation. How much energy is absorbed and emitted is determined firstly by the actual amount of water vapor in the air and secondly by the temperature of the water vapor molecules. So one could argue that it is dependent upon the RH, but not just RH alone. If you'd said RH and temperature you'd have gotten bonus points, but the answer I was after was W (actual vapor mixing ratio) influences radiative transport of energy in the atmosphere.
3. Latent heat: This is the one that is most clearly affected by RH. See the answers to #8 above.