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As a SciShow viewer, you can  keep building your STEM skills with a 30 day free trial and 20% off an annual premium subscription  at Brilliant.org/SciShow. We all have that one friend who  spends a little too long pumping gas.

Taking in all that wonderful, gasoline smell. But unlike the smell of a freshly  baked pie or a newborn baby, gasoline doesn’t seem like one of  those smells that we should like. After all, we don’t get nutrients from  it, we don’t need to look after it, and in a big enough dose,  gasoline can make us really sick.

But it turns out there are  psychological and chemical reasons why so many people love a waft  of this gas-station perfume. [INTRO] Gasoline is made mostly of hydrocarbon molecules, as well as additives that  help the car run smoothly. One of those molecules is benzene,  which gives gas its distinctive smell. But we don’t really know an evolutionary reason to like this random molecule in gasoline.

So it might come down to odor hedonics, which is a science-y way of  saying “we like what we like.” We tend to like familiar smells and those that we’ve formed a positive  association with in the past. So we might have caught a whiff of  benzene while doing something fun like going on a road trip as kids or getting candy from the convenience store. Then we linked those smells  and emotions in our minds.

And it’s easier to link emotions  to smells than other senses because the brain cells that let  us smell things send information to a specialized smell center in the brain before linking directly to the emotion part  of the brain called the amygdala. This pathway is different from our other senses that have to go through a  less specialized intermediate part of the brain before  they’re sent to the amygdala. So that connection between emotion and smell is stronger than, say, taste.

Plus, our brain chemistry  encourages the association. Benzene causes our brains to release  more of the feel-good chemical, dopamine, which makes us feel a bit euphoric. But like many things that  trigger dopamine release, too much of a good thing can be bad.

Inhaling too much benzene can break  our DNA, which causes cells to die. And depending on which cells die, that can mean a weakened immune  system, reproductive problems, or even cancer if you whiff enough of it. So that’s a bit terrifying.

But the good news is: if you’re not a professional  pumper or around gasoline a lot, the amount of benzene you’re  exposed to shouldn’t affect you. Still, it may be best to keep the  time at the pump to a minimum. And if you don’t like the smell of gas, maybe it’s not entirely benzene’s fault.

Because, well, there are a bunch  of other components of gasoline that don’t smell so great. Things like long chain amines  have a fishy or rotten smell, and some people say that long chain  carboxylic acids smell like goats. Which might explain why gasoline  isn’t appealing to all of us.

So there are legitimate reasons why you might love or hate the smell of gas. But whatever camp you fall in, I’m sure we can all agree that the smell of freshly-baked chocolate chip  cookies is much, much better. Learning about chemicals like benzene can really get you wanting more chemistry entertainment.

Like the Brilliant course full  of Chemistry and Biology Puzzles! Brilliant is an online learning platform with courses in math, science, and computer science. And they’ve updated their catalog with tons of new puzzles in each of those categories.

This particular course has  examples of chemical reactions, from camping to rocket fuel.  And it’s a safe way to science, where nothing blows up in your  face. But it will blow your mind. You can check out those puzzles  and more at Brilliant.org/SciShow or at the link in the description down below.

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