How to pump gas

Thanks to my friend Ellen for sharing this forward...

TIPS ON PUMPING GAS

Only fill up your car or truck in the early morning when the ground temperature is still cold. Remember that all service stations have their storage tanks buried below ground. The colder the ground, the more dense the gasoline; when it gets warmer gasoline expands, so when buying in the afternoon or in the evening....your gallon is not exactly a gallon. In the petroleum business, the specific gravity and the temperature of the gasoline, diesel and jet fuel, ethanol and other petroleum products plays an important role.

A 1-degree rise in temperature is a big deal for this business. But the service stations do not have temperature compensation at the pumps.

When you're filling up do not squeeze the trigger of the nozzle to a fast mode. If you look you will see that the trigger has three (3) stages: low, middle, and high. In slow mode you should be pumping on low
speed, thereby minimizing the vapors that are created while you are pumping. All hoses at the pump have a vapor return. If you are pumping on the fast rate, some other liquid that goes to your tank becomes vapor. Those vapors are being sucked up and back into the underground storage tank so you're getting less worth for your money. 

One of the most important tips is to fill up when your gas tank is HALF FULL or HALF EMPTY. The reason for this is, the more gas you have in your tank the less air occupying its empty space. Gasoline evaporates faster than you can imagine. Gasoline storage tanks have an internal floating roof. This roof serves as zero clearance between the gas and the atmosphere, so it minimizes the evaporation. Unlike service stations, here where I work, every truck that we load is temperature compensated so that every gallon is actually the exact amount.

Another reminder, if there is a gasoline truck pumping into the storage tanks when you stop to buy gas, DO NOT fill up--most likely the gasoline is being stirred up as the gas is being delivered, and you
might pick up some of the dirt that normally settles on the bottom.

ALM note:  In case you've seen this forward, you'll notice that I omitted the end part about buying gas from certain companies rather than others in order to avoid supporting Middle East oil companies.  I looked it up on Snopes.com and learned that the information was out of date, if not inaccurate to begin with.

Here's a link to the US Energy Information Administration website, which has current data on petroleum, natural gas, and other energy sources:  http://www.eia.doe.gov/oil_gas/petroleum/info_glance/petroleum.html

P.S. Just today was poring over some GHG data and found this pdf with information about petroleum imports and exports per country, among other factoids, from the International Energy Agency:  http://www.iea.org/Textbase/nppdf/free/2009/key_stats_2009.pdf