got gas?
First, awesome Jenn awesomely got me an awesome gift certificate at thinkgeek. I am beside myself. She's a doll.
The gas craze continues and recently on a road trip we saw an auto shop with the sign proclaiming something like "We have nitrogen : filling your tires with nitrogen saves gas". I'm certain I must have blogged about this before, but it's "hot" again. So let's dispel rumors and spread it out over a few posts for fun.
First, why might people do it? Legitimately, basic compressed air has a lot of moisture, which poses minor concerns for the lifetime of the tire but which is a pain in the neck for NASCAR. Why not use dry compressed air then? Well, I always assumed most air compressors in autoshops had dryers on them, but maybe I'm wrong about that. The moisture issue is nothing new, very minor in the grand scheme of things, and trivial to fix. That would help actually, but race cars and airplanes and the space shuttle also use nitrogen to reduce the fire hazard if a tire should explode. Perhaps Volvo will mandate this as one of its safety features? Hmmmm.
Myth 1. What size are the molecules? Nitrogen gas is composed of diatomic molecules; so is oxygen gas. They are practically the same "size" on a molecule per molecule basis. An individual O atom has a slightly smaller radius than an individual N atom. However nitrogen has a triple bond, while oxygen has a double bond, so that to a good approximation they are the same size. Nonetheless, you will encounter bizaare statements by columnists such as "it replaces skinny oxygen molecules with fat nitrogen molecules". In fact these two gases are so similar, they have nearly the same van der waals constants (please forgive the wikipedia link). That could turn out to be fun and interesting so we'll play with that on another post.