Hank: I'm not here to give you lifestyle advice, so I don't have any official opinion about, say, how the arugula in your salad is fertilized or whether the cotton in your T-shirt was treated for weevils. What I am here for is to help you learn, which is why when I hear 'organic', I don't think groceries, I think chemistry. And in the world of chemistry, you often hear it said than an organic compound is anything with carbon in it, and that organic chemistry is the study of carbon compounds. But kind of like with the arugula and the cotton and the foodstuffs, there's no actual single definition of what 'organic' means in chemistry, and scientists have been arguing about it for a long time, kind of like how moms argue about whose homemade baby food is the healthiest. It usually comes down to whether the stuff you're talking about is simply organic enough. The confusion, as it so often does, has its roots hundreds of years ago. [SciShow intro] Until the 1820s, no one had any idea what chemical compounds made life possible or how they differed from the stuff that was obviously not alive, like rocks, the substances found in people, plants, scorpions, magnificent freaking birds, were all simply thought of as being the product of some vital force, some ineffable power that just made things alive. These substances were called 'organic' or 'organical' because they came from organized living beings. By extension, everything found in objects with no vital force was considered 'inorganic'. So what was it that changed all of that? Man-made pee. In 1828, German chemist Friedrich Wöhler was experimenting with inorganic substances when he combined two of them, aluminum salt and cyanic acid, and accidentally created urea, the main ingredient in animal urine. Because urea was only known to come from living things, it was considered organic, so suddenly, the whole idea of what was organic and what wasn't was up in the air, and it still is. Since then, though, we have come to some important realizations, like we've learned that many compounds that are unique to living things contain carbon, carbon is the neediest of all elements, always begging, nay, demanding, other atoms' electrons. This neediness means that carbon can bond with up to four atoms at a time, which makes for long, strong complex molecules, like amino acids, sugars, lipids, the stuff of life! But still, just because something has carbon, doesn't mean it's alive. Diamonds, for instance, or coal, you wouldn't consider those organic. So since the days of Wöhler, chemists have managed to, if not define what IS organic, at least rule out a few things that aren't. The funny thing is, the distinction usually comes down to 'is it found in living things or not?' Carbides, for instance, are typically considered inorganic because they're made of carbon bonded to an element with a less negative charge, usually heavy metals. Tungsten carbide, for instance, is a super strong carbide used in making machine tools. Carbonates, likewise, are compounds that contain the carbonate ion. Carbonated water has this in abundance, as do minerals like limestone and dolomite, these are all considered inorganic. But, when the ion reacts with other larger compounds that also contain carbon, ,it can form complex molecules like esters, which are important in biology and called organic carbonates. Confused yet? Well, how about this, 'oxides' of carbon are also inorganic, like carbon dioxide, which you and I are exhaling right now, even though it's coming out of your body, you'd be hard pressed to find a chemist in the world who'd call carbon dioxide an organic compound. Why? It all depends on who you ask and what their chemical argument is. Some say that a carbon compound has to be big and complex, which C02 isn't, others argue that organic compounds require a covalent bond, that's where two atoms share an electron between carbon and another element, but that's what C02 has, and no one likes to call that organic. Still others say that organic compounds have to contain carbon bonded with hydrogen, but then that would exclude things like urea, which started this whole debate in the first place, also it would include gasoline. In the end, determining what's organic is kind of like deciding which baby food or arugula is healthiest or who in the Twilight movies is the hottest, everyone has an opinion. Thanks for watching! If you have any questions or comments, we've on Facebook or Twitter or down in the comments below, and if you want to keep getting smarter with us here at SciShow, you can go to YouTube.com/SciShow and subscribe. [Endscreen]