Good morning class. Let’s review one our high school physics lessons. The Combined Gas Law says pV/T = k, where p is pressure, V is volume, T is the temperature (as measured from absolute zero), and k is a konstant. When the value (P * V) goes up (as in when volume increases faster than the pressure decreases), the temperature will drop.
Let’s pretend pressure is 1000 units (of whatever), volume is 10 units, and our temperature is 400 units. Plug those values in, and K = 250. If we drop pressure to 10 units and increase volume to 1000 units, K is still 250 (because it’s a constant), so we can calculate T = 40 units in our imaginary system of units. 40 is obviously much less than 400.
For a real life application, take, for example, this tiny volume of carbon dioxide at high pressure:
… discharged into this large volume 26″ x 2.6″ balloon tire in the rain at the corner of Alma and Lytton in Palo Alto:
The result is an inflater chuck frozen solid to the valve stem:
As an exercise to the reader, discuss this in terms of real world units of pressure, volume and temperature and how the inflater chuck can be removed from the valve stem so I can continue on my journey.