Ideal gas producing less than ideal results

The first version of my Rubens' tube is built, but the results are less than impressive. It's hard to light, the flames are very small, and the standing waves that should be generated by a constant tone aren't very defined. However, it recently occurred to me that my having snagged the propane tank from the gas grill sitting outside in 20 degree weather may be the cause of my problems. Having been outside all winter, the chilled propane in the tank is going to be at a relatively low pressure, which would explain the emaciated-looking flames I observed. Time to bring the propane tank inside and give it some hot cocoa and a warm bed to sleep in to help it re-pressurize.

Perhaps this would be a good example to introduce the ideal gas law to the chemistry class.