T da B, why is my blaster smoking?

The story:
Anyone that has fired a highly pressurized air gun might have noticed an interesting phenomena--a strange mist emanates out the end of your barrel after each shot! Nubs in the forums refer to it as "smoke," but I can assure you that this is not the case. Smoke requires burning, dumbass. Smarter Nerfers will point out that what exits the barrel is actually water vapor. Now you might be wondering why you see this, so here's my explanation.

The science:
Some of you may recall a little something from Physics, or maybe Chemistry as well: the Ideal Gas Law. In case you forgot, here it is:

PV = nRT

P = Pressure
V = Volume
n = # of moles
R = gas constant = 8.314 J/(K*m)
T = Temperature

Another concept we will need to understand for this explanation is dew point. Here is a chart taken from Wikipedia:

The dew point is the temperature below which gaseous water condenses to liquid water. It depends on both temperature and humidity. Unless the humidity is 100%, the dew point is always below the ambient air temperature.

Explanation:
When you pump up your blaster, you are increasing the pressure in your air tank. The more pumps, the higher the pressure. When you pull the trigger, the air rushes out the barrel (path of least resistance) and transitions very quickly from high to low pressure. From the Ideal Gas Law, we know that

P = (nRT)/V

We can now easily see that 

P ∝ T

Pressure is proportional to temperature, so when one increases the other also increases and vice versa. When the pressure drops rapidly, you get a corresponding temperature drop. If the pressure drop and corresponding temperature drop are big enough, the water vapor in the compressed air cools down below the dew point and condenses, allowing us to see it in the same way we see clouds in the sky.