Anyone that drives anywhere is familiar with paying MORE for gas in the summer. I learned last night that most of us are paying MORE than MORE in the summer, thanks to physics (and lack of regulations in the gasoline industry).
This week I’ve been experimenting with homemade thermometers. To make one you fill a bottle with room temperature water, add a few drops of dark food coloring and a straw, and seal the straw in place with some clay. The water level in the straw will change in proportion to the temperature of the thermometer’s surroundings.
Heat is related to the motion of atoms. The molecules in warm water move faster than those in cold water. This increased motion causes warm water to expand, thereby raising the water level in the straw.
What does this have to do with gas prices???
Well, as Jamie Court pointed out in American Public Media’s Marketplace, gas pumps charge us by the gallon, which is a unit of volume. And gas, like water, expands when it gets warm.
Gas companies account for temperature-induced changes in volume when they buy gas from oil companies, but they don’t account for it when they sell it to us (except in Hawaii).
This means that a gallon of gas in the summer has less energy than a gallon during a colder time of year. In warmer areas, he figures, people pay on average 3 centers more than the advertised price of a gallon for a standard gallon’s worth of energy. This overcharging costs Americans about $1.7 billion every year.
Of course you get the good end of the deal if you live in a colder climate. Unless you live in Canada, where they temperature-regulate gas pumps.